1.
Which of the following materials has nearly zero temperature
coefficient of resistance?
a. carbon
c. copper
b. porcelain
d. mangarin
2.
Which of the following materials has a negative temperature
coefficient of resistance?
a. brass
c. aluminum
b. copper
d. carbon
3.
Which of the following statement is true both for a series and
a parallel DC circuit?
a. powers are additive
b. voltages are additive
c. currents are additive
d. elements have individual currents
4.
The superposition theorem is essentially based on the concept
of:
a. duality
c. reciprocity
b. linearity
d. non-linearity
5.
When current flows in a conductor, heat is produced because:
a. heat is directly proportional to the square of the current
b. of electronic collision
c. of interatomic collision
d. of Joule‟s law
6.
Ohm‟s law can be applied with certain reservations to:
a. rectifying devices
c. electrolyses
b. semiconductors
d. thermionic valves
7.
The presence of an electric current is made known by
a. flashing
c. cracking
b. effects produced
d. electric shock
8.
International ohm is defined in terms of resistance of
a. a column of mercury
c. a unit length of metal wire
b. a cube of carbon
d. a cube of copper
1
9.
The capacitance of a capacitor is NOT influenced by
a. plate thickness
c. plate area
b. plate separation
d. nature of the dielectric
10.
A capacitor consists of two
a. insulators separated by a dielectric
b. conductors separated by an insulator
c. ceramic plates and one mica disc
d. silver coated insulators
11.
Point out the WRONG statement
The magnetizing force of the center of a circular coil varies a.
directly as the number of its turns
b. directly as the current
c. directly as its radius
d. inversely as its radius
12.
Permeability in a magnetic circuit corresponds to _______ in
an electric circuit
a. conductivity
c. conductance
b. resistivity
d. resistance
13.
A material commonly
magnetism is
a. brass
b. aluminum
used
for
shielding
or
screening
c. copper
d. soft iron
14.
Iron becomes magnetized by induction when it is
a. heated
b. suspended east and west
c. near to one end of a magnet
d. treated with some chemicals
15.
The relative permeability of paramagnetic substance is
a. slightly less than 1
c. slightly greater to 1
b. equal to 1
d. very much greater than 1
2
16.
Which of the following materials does not have permanent
magnetic dipole
a. paramagnetic
c. diamagnetic
b. antiferromagnetic
d. ferromagnetic
17.
Which of the following materials is used for making permanent
magnets a. carbon steel
b. platinum cobalt
c. alnico V
d. all three mentioned above
18.
The direction of induced emf can be found by
a. Lenz’s law
c. Kirchhoff‟s voltage law
b. Fleming‟s right-hand rule
d. Laplace‟s law
19.
Point out the wrong statement
Magnetic leakage is undesirable in electric machines because it
a. leads to their increased weight
b. increases their cost of manufacture
c. produces fringing
d. lowers their power efficiency
20.
If a current of 5A flowing in a coil of inductance 0.1H is reversed
in 10ms, emf induced in it is ________ volt.
a. 100
c. 1
b. 50
d. 10,000
21.
Permanent magnets are normally made of
a. aluminum
c. cast iron
b. wrought iron
d. alnico alloys
22.
Those magnetic materials are best suited for making armature
and transformer cores which have _______ permeability and
_______ hysteresis loss
a. low, high
c. low, low
b. high, low
d. low, high
23.
Ferrimagnetic materials generally behave as a
a. semi-conductor
c. insulator
3
b. conductor
d. any of a, b, or c
24.
Eddy current loss can be minimized by
a. decreasing the resistance of magnetic medium
b. increasing the resistance of magnetic medium
c. decreasing the permeability of magnetic medium
d. none of these
25.
A collapsing field around a coil
a. tends to opposed the decay of coil current
b. helps the decay of coil current
c. tends to aid current flow reversal
d. does not effect the coil current flow
26.
The capacity of a lead-acid cell does not depend on its
a. rate of charge
c. temperature
b. rate of discharge
d. quantity of active material
27.
Trickle charging of a storage battery helps to
a. prevent sulphation
b. keep it fresh and fully charged
c. maintain proper electrolyte level
d. increase its reserve capacity
28.
A dead storage battery can be revived by
a. a dose of sulfuric acid
b. adding so called battery restorer
c. adding distilled water
d. none of the above
29.
The growth of current in an inductive circuit follows
a. hyperbolic law
c. exponential law
b. ohm‟s law
d. linear law
30.
It is difficult to magnetize steel because of its
a. low permeability
c. high permeability
b. high retentivity
d. high density
4
31.
Hysteresis losses can be reduced by
a. Using grain-oriented silicon steel
b. Increasing the frequency of the field
c. Laminating the core
d. None of these
32.
The unit of field intensity is
a. coulomb
b. coulomb/m2
c. newtons/coulomb
d. none of the above
33.
Dielectric strength of a material depends on
a. moisture content
c. temperature
b. thickness
d. all of the above
34.
If a dielectric is placed in an electric field, the field strength
a. decreases
c. remains the same
b. increases
d. becomes zero
35.
The KW-hr meter can be classified as a/an _____________
instrument
a. deflecting
c. recording
b. digital
d. indicating
36.
The moving system of an indicating type of electrical
instrument is subjected to
a. a deflecting torque
c. a damping torque
b. a controlling torque
d. all of the above
37.
The damping force acts on the moving system of an indicating
instrument only when it is
a. moving
c. near its full deflection
b. stationary
d. just starting to move
38.
Which of the following ammeter will be used to measure
alternating currents only?
a. electrodynamic type
c. induction type
b. permanent magnet type
d. moving-iron
39.
The condition of a liquid electrolyte is measured in terms of
5
its
a. current value
b. specific gravity
c. acid content
d. voltage output
40.
The two main defects of the primary cell are
a. polarization and sulphation
b. local action and polarization
c. buckling and polarization
d. sulphation and buckling
41.
One advantage of a secondary cells is that it
a. can be easily recharged
b. can be sued for portable equipment
c. it is compact, easy to carry
d. cannot be recharged
42.
Electrolyte of a storage battery if formed by adding
a. water to hydrochloric acid
c. hydrochloric acid to water
b. sulfuric acid to water
d. water to sulfuric acid
43.
Induction instrument have found widest applications as
a. voltmeter
c. frequency meter
b. ammeter
d. watthour meter
Induction watthour meters care free from ________ errors
a. phase
c. temperature
b. creeping
d. frequency
44.
45.
Maxwell-Wien bridge is used for measuring
a. capacitance
c. inductance
b. dielectric loss
d. phase angle
46.
The capacitance and dielectric loss of a capacitor is generally
measured with the help of _________ bridge
a. De Sauty
c. Wien series
b. Schering
d. Anderson
47.
The output voltage of a single loop generator is a
a. steady dc
c. pulsating dc
b. steady ac
d. pulsating ac
6
48.
Electric dc generators have normally, an overall efficiency of
the order of
a. 60-80%
c. 80-90%
b. 75-85%
d. 85-95%
49.
The armature magnetic field has effect that
a. it demagnetizes or weakens the main flux
b. it cross magnetizes, or distorts it
c. it magnetizes or strengthens the main flux
d. (a) and (b)
50.
In a dc generator, the flux seem to be ______ at the trailing
pole tips and also _________ at the leading pole tips
a. weakened, weakened c. crowded, weakened
b. weakened, crowded
d. same, same
51.
Electric power is almost exclusively generated, transmitted and
distributed by three phase system because it a. is more efficient
b. use less material for a given capacity
c. costs less than single phase apparatus
d. all of the above
52.
Interpoles are normally connected in
a. parallel with the field c. parallel with the load
b. series with the field
d. series with the load
Carbon brushes are used in electronic motors to
a. brush off carbon deposits on the commutator
b. provide a path for flow of current
c. prevent overheating of armature windings
d. prevent sparking during commutation
53.
54.
If positive phase sequence of a 3 phase load is a-b-c, the
negative sequence would be
a. b-a-c
c. a-c-b
b. c-b-a
d. all of the above
55.
Power factor improvement
7
a. does not effect the performance characteristics of the
original load
b. employs series resonance
c. increases the active power drawn by the load
d. increases the reactive power taken by the load
56.
The chief disadvantage of a low power factor is that
a. more power is consumed by the load
b. current required for a given load power is higher
c. active power developed by a generator exceeds its rated
output capacity
d. heat generated is more than the desired amount
57.
In the two-wattmeter method of measuring three-phase
power, the two wattmeter indicate equal and opposite readings
when load power factor angle is ____ degrees lagging.
a. 60
c. 30
b. 0
d. 90
58.
When phase sequence at the three-phase load is reversed
a. phase powers are changed
b. phase currents are changed
c. phase currents change in angle but not in magnitude
d. total power consumed is changed
59.
The method of symmetrical components is very useful for
a. solving unbalanced polyphase circuits
b. analyzing the performance of 3-phase electrical machinery
c. calculating currents resulting from unbalanced faults
d. all of the above
60.
There are no transients in pure resistive circuits because they
a. offer high resistance
c. have no store energy
b. obey ohm‟s law
d. are linear circuits
61.
The current flowing in the conductors of a DC motor is
a. AC
c. AC as well as DC
b. DC
d. transients
8
62.
The torque of a motor is
a. the force in N-m acting on the rotor
b. the product of tangential force on the rotor and its radius
c. the electrical power in kW
d. the power given to load being driven by the motor
63.
The speed of a series motor at no load is
a. zero
c. 3600 rpm
b. 3000 rpm
d. infinity
64.
If the back emf in a DC motor is absent, then
a. motor will run at very high speed
b. motor will run at very slow speed
c. motor will not run at all
d. motor will burn
65.
For both lap and wave windings, there are a many commutator
bars as the number of
a. poles
c. slots
b. armature conductors
d. winding elements
66.
The only function of dummy coils in a dc armature winding is
to
a. increase the induced emf
b. render the average pitch an integer
c. provide mechanical balance to the armature
d. modify its electrical characteristics
67.
Lap winding is suitable for __________ current, _________
voltage dc generators
a. high,low
c. low, low
b. low, high
d. high, high
68.
The series field of a short-shunt dc generator is excited by
_________ current
a. shunt
c. load
9
b. armature
d. external
69.
Armature reaction is attributed to
a. the effect of magnetic field set-up by the armature current
b. the effect of magnetic field set-up by field current
c. copper loss in the armature
d. the effect of magnetic field set-up by back emf
70.
If the resistance in a series RC circuit is increased, the
magnitude of the phase angle a. increases
b. remains the same
c. decreases
d. changes in an indeterminate manner
71.
The current in RLC series circuit, i.e. at resonance is
a. maximum
c. infinity
b. minimum
d. zero
72.
At
a.
b.
c.
d.
a frequency less that the resonant frequency
series circuit is capacitive and parallel circuit is inductive
series circuit is inductive and parallel is capacitive
both circuits are inductive
both circuits are capacitive
73.
In
a.
b.
c.
d.
dc generators, armature reaction is produced actually by
its field current
armature conductors
field pole winding
load current in armature
74.
Shunt generators are most suited for stable parallel operation
because of their ________ voltage characteristics
a. identical
c. linear
b. drooping
d. rising
10
75.
Two parallel shunt generators will divide the total load equally
in proportion to their kilowatt output ratings only when they
have the same
a. rated voltage
c. internal laRa drops
b. voltage regulation
d. both (a) and (b)
76.
The main function of an equalizer bar is to make the parallel
operation of two over-compounded dc generators
a. stable
c. regular
b. possible
d. smooth
77.
A coil with large distributed capacitance has a
a. low resistance
b. low Q
c. low resonant frequency
d. high resonant frequency
78.
Which if the following is not a non-linear element?
a. diode
b. transistor
c. heater coil
d. electric arc with unlike electrodes
79.
For maximum power transfer, according to maximum power
transfer theorem, source impedance
a. must be very much large as compared to the load
impedance
b. must be complex conjugate of load impedance
c. must be equal to load impedance
d. must be very small as compared to the load impedance
80.
Ideal transformer assumptions do not include
a. zero reactance of windings
b. zero resistance of windings
c. no leakage flux
d. no saturation of core
81.
If residual magnetism of a shunt generator is destroyed
accidentally, it may be restored by connecting its shunt field
11
a. to earth
b. to an arc source
c. in reverse
d. to a dc source
82.
An ideal generator is one that has __________ voltage
regulation
a. low
c. positive
b. zero
d. negative
83.
The __________ generator has poorest voltage regulation
a. series
c. shunt
b. compound
d. over compound
84.
The counter emf of a dc motor
a. often exceeds the supply voltage
b. aids the applied voltage
c. helps in energy conversion
d. regulates its armature voltage
85.
The resistance of low voltage side of a transformer
a. is equal to resistances of its high voltage side
b. is more than resistance
c. is less than the resistance of its high voltage side
d. (b) or (c)
86.
What type of core is used for a high frequency transformer?
a. air core
c. aluminum core
b. closed iron core
d. open iron core
87.
In any transformer the voltage per turn in primary and
secondary remains
a. always different
c. always in ratio K
b. always same
d. sometimes same
88.
The size of a transformer core will depend on
a. frequency
b. flux density of the core material
c. area of the core
d. both (a) and (b)
12
89.
Under constant load conditions, the speed of a dc motor is
affected by
a. field flux
c. back emf
b. armature current
d. both (b) and (c)
90.
A series motor is best suite for driving
a. lathes
c. sheares and punches
b. cranes and hoists
d. machine tools
91.
The shaft torque of a dc motor is less that it armature torque
because of _____________ losses
a. copper
c. iron
b. mechanical
d. rotational
92.
The speed of a dc motor ca be controlled by varying
a. its flux per pole
b. resistance of armature circuit
c. applied voltage
d. all of the above
93.
High speed alternators have a rotor construction
a. similar to dc machines
c. of salient type
b. of non-salient type
d. none of the above
94.
Distributing the armature winding of alternator in more than
one number of slots per pole phase results in
a. reduction of irregularities produced in waveform
b. economy of materials used in winding
c. less weight of the entire armature
d. increase of generated emf per phase
95.
When the power factor of load is unity, the armature flux of an
alternator will be
a. demagnetizing
c. cross magnetizing
b. square wave form
d. none of these
96.
The maximum current that can be supplied by alternator
depends upon the
a. strength of the exciter voltage
13
b. number of poles
c. strength of the magnetic field
d. maximum heat dissipation
97.
Controlled rectifiers employ
a. diodes
c. bridge circuits
b. thyristors
d. both (a) and (b)
98.
When a 400Hz transformer is operated at 50Hz, its kVA rating
is
a. reduced to 1/8
c. unaffected
b. increased 8 times
d. increased 64 times
99.
The primary and secondary windings of an ordinary 2-winding
transformer always have
a. different number of turns
b. same size of copper wire
c. a common magnetic circuit
d. separate magnetic circuits
100. At
a.
b.
c.
d.
relatively light loads, transformer efficiency is low because
secondary output is low
transformer losses are high
fixed loss is high in proportion to the output
Cu loss is small
101. Adjustment of field excitation on one of the two alternators
operating in parallel will
a. increase its load
c. decrease its load
b. change in frequency
d. change its power factor
102. Synchronizing motors are
a. self-starting
c. essentially self-starting
b. not self-starting
d. none of these
103. A 3 phase synchronous motor is running clockwise. In case the
direction of its field current is reversed
a. the motor will continue to run in the same direction
14
b. the motor will run in the reverse direction
c. the motor will stop
d. the winding of the motor will burn
104. The all-day efficiency of a transformer depends primarily on
a. its copper loss
c. the duration of load
b. the amount of load
d. both (b) and (c)
105. The essential condition for parallel operation of two single
phase transformers is that they should have the same
a. polarity
c. voltage ratio
b. kVA rating
d. percentage impedance
106. Instrument transformers are used on ac circuits for extending
the range of
a. ammeters
c. wattmeters
b. voltmeters
d. all of the above
107. The principle of operation of a 3-phase induction motor is most
similar to that of a a. synchronous motor
b. repulsion-start induction motor
c. transformer with a shorted secondary
d. capacitor-start, induction-run motor
108. When a 3 phase synchronous generator is supplying a zero pf
lagging load the armature field affects the main field in the
following way
a. directly opposes it
c. augments it directly
b. cross-magnetizes it
d. none of the above
109. Improvement in the power factor in an induction motor
a. decreases torque
b. increases the torque
c. increases the current
d. increases the torque and decreases the current due to
increased impedance
110. Short circuit test on the induction motor can be used to find
out
15
a.
b.
c.
d.
the transformation ration of the impedance motor
power scale of circle diagram
copper losses in the induction motor
all of the above
111. If the air gap of the induction motor is increased
a. the magnetizing current will decrease
b. the magnetizing current will increase
c. the power factor will decrease
d. none of the above
112. If starting winding of a single phase induction motor is left in
the circuit, it will
a. draw excessive current and overheat
b. run slower
c. run faster
d. spark at light loads
113. If a single phase induction motor runs slower than normal, the
more likely defect is
a. improper fuses
c. open starting winding
b. shorted running winding
d. worn bearings
114. A permanent split single-phase capacitor motor does not have
a. centrifugal switch
c. squirrel-cage rotor
b. starting winding
d. high power factor
115. Zero power method of an alternator is used to find its
a. efficiency
c. armature resistance
b. voltage regulation
d. synchronous impedance
116. Is a device which functions on failure of the insulation of a
machine, transformer or of other apparatus to ground or on
flash over of a dc machine to ground
a. overhead ground relay
c. grounding reactor relay
b. ground insulation relay
d. ground protective relay
117. Is an equipment which controls the gate or valve opening of
prime mover
a. silicon controlled rectifier
c. rheostat
16
b. contactor
d. governor
118. Is the mechanism which is used for moving a removable circuit
breaker unit to end from the connected, disconnected and test
positions
a. permissive control device
b. notching device
c. blocking device
d. position changing mechanism
119. Is the complete electrical mechanism or servo-mechanism
including the operator motor, solenoid, position, switches, etc.,
for a tap change, induction regulator or any piece of apparatus
which has no device function number
a. regulating device
c. rotating device
b. reversing device
d. operating mechanism
120. Is use to increase or decrease in one step the value of field
excitation on a machine a. tripping relay
b. field regulator
c. DC reclosing relay
d. field changing contactor
121. A special type of diode used to regulate dc voltage supply
a. Thyristors
c. Diac
b. Zener
d. Shockley
122. Electrons normally flow
a. from the grid to the plate of an electron tube
b. from the positive terminal to the negative terminal inside
the battery
c. through a capacitor
d. at the speed of light in a conductor
123. When an electric current is flowing in a conductor, heat is
developed at a rate proportional to the square of the intensity
of the current. This relation is known as
a. Coulomb‟s law
c. Faraday‟s law
b. Joule’s law
d. Ohm‟s law
17
124. An electric device designed to receive electrical power from a
dc source and deliver alternating power without the aid of
external source of alternating voltage
a. amplifier circuit
c. rectifier circuit
b. oscillator circuit
d. integrated circuit
125. The modulated wave is transmitted over lines or space.
However at the receiving end, the signal wave must be
recovered again by means of electronic circuit called a.
frequency changer c. filter
b. detector
d. inverter
126. Process by which the characteristics of a wave is varied as a
function of the instantaneous value of another wave
a. detection
c. phase shifting
b. modulation
d. feedback
127. In any network consisting of linear impedances, the current at
any point is the sum of the currents that would flow if each
generator were considered separated all other generators
being replaced at the time by impedances equal to their
internal impedances. This principle is known as
a. Kirchhoff‟s law
c. Thevenin‟s Theorem
b. Superposition Theorem
d. Reciprocity Theorem
128. When the emfs in the two windings of the transformer are
opposite in direction, the polarity is
a. positive
c. additive
b. negative
d. subtractive
129. For a transducer, the impedance which will simultaneously
terminate all of its inputs and outputs in such a way that each
of its inputs and outputs, the impedances in both directions are
equal are called
a. iterative impedances
c. characteristics impedances
b. image impedances
d. driving impedances
130. To determine the equivalent resistance of an inductive motor,
we use
a. no load test
c. blocked rotor test
18
b. short circuit test
d. polarity test
131. Consisting of a single rotating machine that is mainly to convert
alternating current to direct current
a. motor generator set
c. rotary converter
b. motor converter
d. mechanical rectifier
132. It is the ration of lumens reaching the work plane by the total
lumens generated by lights
a. maintenance factor
c. coefficient of utilization
b. room ratio
d. room index
133. Intermittent operation in which the load conditions are
regularly recurrent
a. short time duty
c. periodic duty
b. continuous duty
d. varying duty
134. In a dc machine, this consists of coils placed at the neutral point
midway between the main poles
a. compensating winding
c. interpole winding
b. equalizer winding
d. neutralizer winding
135. A connection to ground for one or more non-carrying metal
parts of the wiring system or apparatus connected to the
system
a. system ground
c. equipment ground
b. system neutral ground
d. capacitive ground
136. A transformer intended primarily to provide neutral point for
grounding purposes
a. ground regulating transformer
b. ground equalizer transformer
c. grounding transformer
d. ground fault transformer
137. A grounding transformer may be connected zigzag of
a. delta-delta
c. wye-delta
b. delta-wye
d. wye-wye
19
138. Of the lighting arresters sold in the market, which can handle
much surge current and excessive contamination of dirt a.
distribution arrester c. station arrester
b. line arrester
d. intermediate arrester
139. It is a disruptive discharge between electrodes of measuring
gap, voltage control gap, or protective device
a. flashover
c. sparkover
b. corona
d. fireover
140. The voltage that insulation is capable of withstanding without
failure or disruptive discharge when tested under specified
conditions
a. maximum withstand voltage
b. rated withstand voltage
c. c. critical withstand voltage
d. minimum
141. In symmetrical components, the components consisting of
balanced 3 phase vectors and having a phase sequence
opposite to that of the given vector is a. additive sequence
system
b. subtractive sequence system
c. negative sequence system
d. positive sequence system
142. The fault current that exists immediately after the fault is
known as
a. transient current
c. subtransient current
b. steady state current
d. sustained current
143. The insulation strength of an equipment is described as its
a. basic insulation strength
c. basic insulation level
b. basic impulse stress
d. basic insulation factor
144. In hydroelectric power plant, it is used to prevent the sudden
rise and drop of water pressure.
a. penstock
c. dam
b. intake tower
d. surge tank
20
145. To test the accuracy of a kilowatthour meter an electrician used
a wattmeter. He found out that the meter makes 5 revolutions
in 18 seconds. The meter constant is 3.2. What is the percent
error if the wattmeter reading is 3,368?
a. 8% slower
c. 5% slower
b. 8% faster
d. 5% faster
146. A 100 MW power plant burns 0.4 kg of coal with heating value
of 7.2 x 106 calories per kg to produce 1 KwHr. If the power
plant acts as a base load, how many tons of coal per day is
consumed if the power plant operates 24 hours per day?
a. 530
c. 830
b. 960
d. 260
147. An amplifier has an output of 50 watts. What is its output in
dbm?
a. 47
c. 75
b. 50
d. 80
148. How is the storage battery rated in capacity?
a. volts
c. amperes
b. watts
d. ampere – hour
149. The basis where the flow of current is from positive to negative
was derived from _____
a. superstition
c. scientific
b. tradition
d. convention
150. A 220 volts dc series motor when running at 800 rpm draws a
current of 100 amperes. The combined resistance of the
armature and the field is 0.1 Ω. What is the speed when the
motor develops one – half of the original torque?
a. 1,600 rpm
c. 1,147 rpm
b. 1,690r pm
d. 1,225 rpm
151. The fault current that exists immediately after the fault is
known as:
a. sub – transient current
c. steady – state current
b. transient current
d. sustained current
21
152. Its primary function is to provide ground source
a. zig – zag transformer c. surge arrester
b. sectionalizer
d. tertiary transformer
153. The following are the given loads of a particular circuit:
5 – 15 hp motors
3 – 5 hp motors
8 kw – lighting loads
3.5 kw – miscellaneous loads
Calculate for the maximum demand if the demand factor is
65%.
a. 78.64
b. 45.81
c. 51.12
d. 120.98
154. An SCR‟s three leads are the:
a. anode, cathode and emitter
b. anode, cathode and gate
c. base 1, base 2, and emitter
d. main terminal 1, main terminal 2, and gate
155. A 20 kv/7.87 kv autotransformer has a secondary line current
of 100 A. What is the current in the common winding?
a. 139.25 A
c. 60.65 A
b. 100 A
d. 39.35 A
156. A 220 volts single – phase induction motor draws current of 10
amperes at 0.75 power factor. A capacitor of 50 µF is connected
in order to improve the power factor. What is the new power
factor?
a. 0.866 leading
c. 0.95 lagging
b. 0.866 lagging
d. 0.95 leading
157. A 3Φ 220 volts, 10 hp induction motor having a power factor
of 0.8 has 3% losses. Determine the current drawn by the
motor.
a. 25.23 A
c. 20.18 A
b. 43.69 A
d. 14.56 A
22
158. A solenoid having an inductance of 12 henry is impressed
across a voltage source such that the current through it is 3
amperes. What is the average voltage at t = 0.2 sec?
a. 150 volts
c. 120 volts
b. 180 volts
d. 220 volts
159. An electric heater takes 23.889kcal in 20 minutes at 200 volts.
What is the current drawn by the heater?
a. 8.4 A
c. 1.67 A
b. 16.67 A
d. 0.42 A
160. A series RLC circuit has a resistance of 15 Ω and an inductive
reactance of 1,500 Ω. What is the Q – factor of the circuit at
resonance?
a. 120
c. 140
b. 100
d. 150
161. A synchronous motor that is used for power factor correction
only.
a. synchronous reactor
c. generator
b. alternator
d. synchronous condenser
162. Why are transmission towers sometimes constructed in lattice
type and sometimes in pole type although they have the same
capacity and voltage rating?
a. reliability
c. right of way
b. wind load
d. safety
163. The capacitive reactance of a transmission line is 90,000 ohms
per kilometer. Find the total capacitive reactance if the
transmission line is 50km long.
a. 4.5x 106 Ω
c. 90,000 Ω
b. 1,800 Ω
d. 180,000 Ω
164. An 80 µF capacitor in series with 1,000 Ω resistor is connected
suddenly across a 110 V supply. Find the rate at which current
begins to decrease.
a. 13.75 A/s
c. 1.375 A/s
b. 0.1375 A/s
d. 137.5 A/s
23
165. A 100 watts 230 volts gas fitted lamp has a mean spherical
candlepower of 92. Find its efficiency in lumens per watt.
a. 11.56
c. 115.6
b. 1.156
d. 1,156
166. Charges that are both positively and negatively charged are
called:
a. negatron
c. neutron
b. neutraton
d. positron
167. With the primary of CT energized, the secondary must never
be made open to prevent this to happen. a. build up of
magnetic bias
b. burning of primary winding
c. burning of secondary winding
d. absence of induced voltage
168. A 25 miles (40 km), 3Φ, 3 wire sub transmission line with an
impedance per conductor of (7.65 + j16.52) Ω is supplying a
balanced 3Φ load of 4,000 kw, 33,500 volts line to line, 60 hz
at 0.8 p.f. lagging. The conductors used in the line are 336.4
MCM, ACSR, 26/7 strands vertically spaced 4.5 ft apart. If a
2,100 kvar, 3Φ pure capacitor bank is installed across the load,
what is the voltage dip maintaining 33,500 volts at the
receiving end?
a. 735 V
c. 585 V
b. 635 V
d. 485 V
169. A symmetrical cable with 200 meters span has a unit weight of
2 kg-force per meter uniformly distributed along the horizontal.
The tension at the lowest point is 2,000 kg-force.
Find the tension at the supports in kg-force.
a. 2,010
c. 4,080
b. 2,040
d. 2,000
170. The positive-sequence components of the system has
a. the same phase-sequence as the original
b. the opposite phase-sequence as the original
c. zero-phase displacement
d. both a and b
24
171. A voltmeter rated 150 volts has an internal resistance of 10 kΩ.
What resistance should be added in series to the internal
resistance so that the voltmeter will register full scale deflection
across 450 V?
a. 6.67 kΩ
c. 40 kΩ
b. 30 kΩ
d. 20 kΩ
172. Pilot lamp in a MCC indicates a motor control center
a. underload
b. overload
c. normal condition of the load
d. out of order
173. A south pole 20 unit pole is placed one inch away from another
south pole 35 unit pole. What is the force between the two
poles?
a. 108.5 dynes repulsion c. 70 dynes repulsion
b. 108.5 dynes attraction
d. 70 dynes attraction
174. In a 34.5 kv three-phase system, the Thevenin‟s equivalent
impedances are
Positive impedance, Z1 = 0.015 p.u. at 50 MVA
Zero impedance, Z0 = 0.03 p.u. at 50 MVA
What is the phase to phase fault current?
a. 48,000 A
c. 8,400 A
b. 80,000 A
d. 32,000 A
175. This is an electrically operated switch which is rated in amperes
and is also used in overload protection of motors. a. magnetic
starter c. magnetic contractor
b. safety switch
d. manual starter
176. These are high intensity discharged lamps which are usually
installed in outdoor and wide areas and are mounted on poles
whereas for indoors these are used for high ceiling applications.
a. surfaced
c. low mount
b. recessed
d. high bay
25
177. What do you call an insulated conductor that can be used only
up to 300 volts and is considered having no insulation base on
general rating?
a. insulated conductor
c. enameled conductor
b. base conductor
d. covered line wire
178. What is the field intensity E in millivolts per meter of an
omnidirectional antenna over a distance of 1 km if the power is
1 kw? (impedance of free space is 120∏)
a. 153.4
c. 120
b. 150
d. 173.32
179. A limit switch is used to shut off the power when _____ a
definite limit.
a. current exceeds
c. the travel reaches
b. voltage falls below
d. frequency exceeds
180. A magnetic circuit consists of silicon steel of 2000 permeability
of 10 cm length and cross sectional area and of 1 centimeter
length. A one – ampere current flows through 500 turns of coil.
Calculate the field intensity across the air gap.
a. 622 Oersted
c. 590 Oersted
b. 755 Oersted
d. 350 Oersted
181. Find the GMD of a double circuit having vertical configuration 3
meters apart and 3 meters between conductors. The phase
configuration of the 1st circuit is ABC from top to bottom and
the 2nd circuit is CBA.
a. 4.24 m
c. 3.567 m
b. 3.78 m
d. 3 m
182. A relay coil carries a polarizing current of 1 A dc and a signal
ac current of 3 A at 50 hz. If coil resistance is 5 Ω, power
dissipated by the coil is ___ watts.
a. 50
c. 5
b. 80
d. 20
183. For a 4-pole dc generator, having a progressive simplex 2layer
wave – winding with 30 conductors, the commutator pitch is
___
a. 8
c. 10
26
b. 9
d. 11
184. Rapid stopping of an electric motor by momentarily reversing
its connections to the supply is called
a. jogging
c. plugging
b. inching
d. sequence operation
185. A certain 1Ф load takes 10 kw at 75 percent power factor. In
the power contract the power factor penalty is applied only to
power factors below 85 percent. What size of capacitor must
be used in order to avoid the penalty? The voltage is 550 volts,
60 cycles.
a. 92.82 µF
c. 2.98 µF
b. 9.82 µF
d. 22.98 µF
186. An induction motor driven above synchronous speed is called
___.
a. induction regulator
c. centrifugal switch
b. zero – speed switch
d. limit switch
187. A 200 kva transformer has an impedance of 15% and the power
factor of the load is 85%. The primary voltage is 6,000 volts
while the copper loss is 15 kw. Find the percentage voltage
regulation.
a. 13.49%
c. 8.91%
b. 15.78%
d. 23.67%
188. What is the speed of an induction motor of six poles if the
percent slip is 2.5%?
a. 1462 rpm
c. 877 rpm
b. 1170 rpm
d. 1755 rpm
189. The rotor poles of an 8 – pole synchronous generator shift by
10 mechanical degrees from no –load to full – load. Calculate
the torque angle between the excitation voltage E0 and the
terminal voltage VФ at full – load.
a. 10º
c. 30º
b. 20º
d. 40º
27
190. This is a device projected vertically upward above structures to
serve as the lighting rod.
a. air connector
c. air terminal
b. lightning bowl
d. air rod
191. A transformer is designed to carry 30 times its rated current
for 1 second. The length of time that a current of 20 times the
rated current can be allowed to flow is
a. 0.67 sec.
c. 1.5 sec
b. 2 sec
d. 2.25 sec.
192. What is the normal secondary circuit current of a current
transformer?
a. 15 A
c. 5 A
b. 20 A
d. 10 A
193. A parallel circuit has branch resistance of R1 =20 Ω, R2 =10 Ω,
R3 =5 Ω. If the current passing through R1 =20 Ω resistor is 1
ampere, what is the current passing through the 10 Ω resistor?
a. 5 A
c. 3 A
b. 2 A
d. 4 A
194. In a stranded conductor, what do you call the strand at the
center of the conductor?
a. king wire
c. steel wire
b. center wire
d. center
195. The total power consumed by a balanced 3Ф load is 3,000 watts
at 80% power factor. Two wattmeters WA and WB are
connected to the line. What is the reading of WA?
a. 2,150 watts
c. 1,500 watts
b. 2,000 watts
d. 2,500 watts
196. A circuit with a resistance of 10 Ω is supplied with 120 V 60 hz
source. What is the phase angle between the voltage and the
current?
a. 45º
c. 30º
b. 15º
d. 0º
28
197. What is the synchronous speed in rpm of a 6 - pole 60 cycle
induction motor?
a. 1,200
c. 3,600
b. 1,800
d. 900
198. A 3 phase 4 wire system has the following unbalanced loads:
Z1= (10+j5) Ω, Z2= (8+j4) Ω and Z3= (20+j0) Ω. The line to
neutral voltage of the system is 120 volts. What is the reading
of the wattmeter in watts in Z3?
a. 900
c. 1,000
b. 720
d. 1,050
199. What electrode in a junction transistor corresponds to the
cathode in vacuum tube?
a. base
c. drain
b. emitter
d. collector
200. An AC circuit with two resistances, which is correct?
a. a 1,000 ohm resistance in series to 500 ohm has a total of
6,000 ohms.
b. Two 1,000 ohm resistances in series has a total of 1,500
ohms.
c. Two 1,000 ohm resistances in series has a total of 707 ohms
d. Two 1,000 ohm resistances in series has a total of 2,000
ohms.
201. Which does not belong?
a. lines per square centimeter
b. maxwells per square centimeter
c. flux
d. gauss
202. The diameter of a conductor is 0.064 inch. What is the area in
circular mils?
a. 5,000
c. 3,217
b. 10,000
d. 4,096
203. In a shunt motor, what is the relative connection of the
armature winding with respect to the field winding?
a. series
c. series – parallel
29
b. parallel – series
d. parallel
204. A single – phase 2,400 volt synchronous generator draws 450
amperes at unity power factor. The synchronous impedance of
the generator is (0.08 + j2.8) Ω. What is the regulation in
percent?
a. 14.2
c. 20.1
b. 16.3
d. 18.4
205. A pure semiconductor without doping is called
a. contaminated
c. doped
b. extrinsic
d. intrinsic
206. A series RLC circuit has R = 10 Ω, L = 40 x 10 -6 H and C = 60
x 10-12 F. What is the resonant frequency of the circuit in MHZ?
a. 20.17
c. 4.49
b. 3.24
d. 1.62
207. On full – load a 500 volt series motor takes 100 amperes and
runs at 840 rev/min. The armature resistance is 0.1 ohm and
field resistance is 0.04 ohm. Find the speed when developing
half of full – load torque but with a 0.08 ohm diverter in parallel
with the field winding. Assume flux is proportional to the field
current.
a. 640 rpm
c. 1,464 rpm
b. 1,020 rpm
d. 1,360 rpm
208. A capacitor charged with 10,000 µC. If the energy stored is 1
joule, find the capacitance.
a. 500 µF
c. 5,000 µF
b. 5 µF
d. 50 µF
209. A 440 volt synchronous motor is taking 50 amperes at a p.f. of
0.9 lagging. The effective resistance of armature is 0.8 ohm. If
the iron and friction losses amount to 600 watts, find the horse
power output.
a. 25.7
c. 23.1
b. 37.1
d. 40.5
30
210. Three 100 µF capacitors are connected in delta to a 500 volt,
three phase, 50 Hz supply. Find the line current.
a. 15.71 A
c. 31.83 A
b. 27.21 A
d. 8.66 A
211. A pair of copper mains. Each of 3.87 square centimeters cross
section is used to transmit power a distance of 915 meters. For
10 hours a day, 80 kW at 200 volts are taken from the mains.
Find the energy lost in the cables per day. Take ρ = 1.7 micro
ohm – cm.
a. 64 kW-hr
c. 256 kW-hr
b. 128 kW-hr
d. 32 kW-hr
212. An SCR combines the features of
a. a rectifier and resistance
b. a rectifier and capacitor
c. a rectifier and transistor
d. a rectifier and inductor
213. A 0.09 microfarad capacitor is charged to 220 volts. How long
in milliseconds will it discharged to a level of 110 volts if the
discharged resistor has a resistance of 20,000 ohms?
a. 1.5
c. 1.25
b. 2.5
d. 0.5
214. The total generating capacity of a power plant is 1,600 kva.
The total connected load is 2,500 kva. Average load is 1,145
kva. The maximum power demand is 1,150 kva. What is the
plant factor?
a. 46%
c. 71.88%
b. 99.5%
d. 71.56%
215. Assuming the most efficient technologies for the extraction of
energy, the fuel with the largest known reserves is
a. coal
c. natural gas
b. oil
d. nuclear
216. A three – phase 60 hz line has flat horizontal spacing. The
conductors have an outside diameter of 3.28 cm with 12 m
between conductors. Determine the capacitive reactance of the
line to neutral if its length is 125 miles.
31
a. 1.62 x 103 Ω
b. 202.4 x 103 Ω
c. 25.3 x 106 Ω
d. 16.2 x 103 Ω
217. Name of the transformer that provides an almost continuously
variable step-less output voltage from zero to rated line
voltage.
a. booster
c. AVR
b. UPS
d. Variac
218. A circuit has a resistance of 20 Ω and a reactance of 30 Ω.
What is the p.f. of the circuit?
a. 0
c. 0.832
b. 0.55
d. 0.99
219. A parallel branch circuit composed of a 100 ohm resistance,
150 ohm capacitive reactance and 90 ohm inductive reactance.
What is the total impedance of the circuit?
a. 125
c. 91
b. 100
d. 97
220. The most common type of the conductor used for overhead
transmission lines consisting of electrical grade aluminum
conductor overlaying strands of high carbon galvanized steel is
called:
a. ACAR
c. COMPACT STAND AL
b. ACSR
d. AAC
221. The 65 percent taps on a compensator are used in connection
with a 10 hp 220 volt three phase motor. Rated motor current
is 26.4 amp, and blocked – rotor current at 220 volts is 150
amp. Calculate the percent motor current in terms of rated
amperes.
a. 369
c. 240
b. 65
d. 568
222. A single – phase transformer is rated 110/440 V, 2.5 kVA.
Leakage reactance measured from the low – tension side is
0.06 Ω. Determine leakage reactance in per unit.
a. 0.0484
c. 0.484
b. 0.0248
d. 0.0124
32
223. Three capacitors of 50 µF, 30 µF, and 10 µF are connected in
parallel. What is the total capacitance in microfarad?
a. 15 µF
c. 100 µF
b. 90 µF
d. 115 µF
224. What is the process of heating electrically non metallic
materials such as plumber plastics, etc.?
a. resistive
c. dielectric
b. capacitive
d. induction
225. If a fault occurs near a generating station, how long does the
transient component of the fault last?
a. 10 to 15 sec
c. 3 to 5 sec
b. 5 to 10 sec
d. 1 to 3 sec
226. A three – phase 60 Hz, 30 mile transmission line delivers
20,000 kW at 69,000 volts and 75% power factor lagging. The
resistance of the line is 0.3 ohm per mile and the reactance is
0.7 ohm per mile. What is the transmission line efficiency?
a. 93
c. 95
b. 94
d. 96
227. How are multiple stop push buttons connected in a control
circuit?
a. combination series – parallel
b. parallel
c. gang
d. series
228. A road is illuminated by two 500 candela lamps placed 6.1
meters above the center line of the road and 18.3 meters apart.
Find the illumination produced on the surface of the road at a
point on the center line midway between lamps.
a. 2.29 lux
c. 9.16 lux
b. 4.58 lux
d. 18.32 lux
229. A heater contains 1.6 kg of water at 20ºC. It takes 12 minutes
to raise the temperature to 100ºC. Assume the losses due to
radiation and heating the kettle to be 10 kcal. Find the power
rating of the heater in kW.
33
a. 0.74
b. 0.7
c. 0.84
d. 0.8
230. Shunts are generally made of what material?
a. constantan
c. aluminum
b. silver
d. manganin
231. A magnetizing force of 1,000 At/m will produce a flux density
of ____ in air.
a. 1.257 mWb/m2
c. 1.257 Wb/m2
b. 0.63 Wb/m2
d. 0.63 mWb/m2
232. The potential difference of a battery is 10 volts when the
current is 1.5 amperes and 8 volts when the current is 2.5
amperes. Find the internal resistance of the battery.
a. 1 Ω
c. 3 Ω
b. 2 Ω
d. 4 Ω
233. A four pole, lap wound armature when driven at 600 rpm
generates 120 V. If the flux per pole is 25 mWb, find the
number of armature conductors.
a. 120
c. 480
b. 240
d. 720
234. A coil of 1,000 turns is uniformly wound on ring of non –
magnetic material, the mean diameter being 0.2 meter. The
cross –sectional area of the coil is 4 cm2, with a current of 2
amperes flowing, find the total flux in µWb.
a. 3.2
c. 1.6
b. 6.4
d. 4.8
235. What are the three colors which when mixed equally together
will produce white and the combination of any two will produce
different colors and intensities?
a. red, blue, green
c. black, red, pink
b. yellow, magenta, cyan
d. red, blue, yellow
236. A 500 kV line is categorized as
a. high voltage
b. ultra high voltage
c. extra high voltage
d. medium voltage
34
237. A circuit having a resistance of 20 Ω and an inductance of 0.5
H is connected suddenly across a 220 V supply. Find the rate
of increase of current at the instant of closing the switch.
a. 440 A/s
c. 120 A/s
b. 220 A/s
d. 480 A/s
238. A 350 kW, 2,300 V, three – phase resistive load is measured
with two small wattmeters. Two 100/5 A current transformers
and two 2,300/115 V potential transformers make this
possible. Calculate the reading on each wattmeter.
a. 874 W & 874 W
c. 1,311 W & 1,311 W
b. 218 W &218 W
d. 437 W & 437 W
239. The transformer is rated at 550/220 V. With the low –voltage
winding shorted, it requires 25 V across the 550 V winding to
permit rated current through both windings of the transformer.
Calculate the percent impedance.
a. 4.55%
c. 3.55%
b. 5.55%
d. 6.55%
240. A group of 10 luminaries, each with two 40 watt, cool – white
fluorescent lamps, are installed in a classroom. An appropriate
CU of 0.65 is selected from the manufacturer‟s chart, which
also suggests an MF of 0.85. Determine the total lumens output
of the luminaries.
a. 58,000
c. 32,100
b. 26,000
d. 64,200
241. A central station has annual factors as follows:
Load = 58.5%
Capacity = 40.9%
Use = 45.2%
The reserve carried over and above the peak load is 8,900kw.
What is the installed capacity?
a. 20,700 kW
c. 25,900 kW
b. 29,600 kW
d. 40,000 kW
242. A 12 µF capacitor charged at 500 volts and a 6 µF capacitor
charged at 250 volts are connected in parallel. What is the
potential difference of the combination?
35
a. 750 V
b. 500 V
c. 375 V
d. 417 V
243. An antenna that transmits or receives equally well in all
directions is said to be __________
a. omni directional
c. unidirectional
b. bi-directional
d. quasi-directional
244. A 30 mile transmission line is to deliver 20,000 kW at 69 kV at
85% power factor. The line resistance is 0.324 ohm per mile
and inductive reactance is 0.737 ohm per mile. What is the line
loss?
a. 1,050 kW
c. 997 kW
b. 376.7 kW
d. 1,130.3 kW
245. Prior to starting of fluorescent lamp, heating of electrode is
done by
a. starter
c. filament
b. ballast
d. heater
246. A frequency of
27
MHz has a
of approximately______.
a. 11 m
c. 27 m
b. 30 m
d. 81 m
wavelength
247. A type of communication that uses light rather than electricity
to communicate is called_____.
a. laser carrier
c. powerline carrier
b. microwave
d. fiber optic
248. A copper wire has a diameter of 0.032 inch. What is the area
in circular mils?
a. 1,288
c. 810
b. 1,024
d. 1,624
249. It is required to increase the power factor of a 750 kW three –
phase balanced load from 70% lagging to 90% lagging. The
line voltage is 6,900 volts, 60 hz. Specify the capacitor required
to increase the power factor of this wye – connected load in
microfarad per phase.
36
a. 20.45
b. 22.39
c. 18.58
d. 17.22
250. A signal occupies the spectrum space from 1.115 to 1.122 GHz.
The bandwidth is____.
a. 0.007 MHz
c. 237 MHz
b. 700 MHz
d. 7 MHz
251. Two condensers of 3 and 5 µF respectively are connected in
parallel. The combination is charged with 0.0056 coulomb.
What is the charge in the 3 µF condenser in coulombs?
a. 0.01
c. 0.0021
b. 0.005
d. 0.0035
252. A series circuit with 10 ohm resistor and 50 µF capacitor is
suddenly connected to a dc source of 120 volts. What is the
current at one time constant?
a. 12 A
c. 7.6 A
b. 2.44 A
d. 4.4 A
253. A room with dimensions of 72 ft x 36 ft x 13 ft requires 50
footcandles, maintenance factor of 0.7 coefficient of utilization
of 0.46 and Rl of 4. Calculate the required lumens output of the
lamps.
a. 144,000
c. 402,485
b. 136,800
d. 74,690
254. Instrument transformers are used in indicating and metering
and with protective devices, they are used for ______
a. measuring
c. relaying
b. detecting
d. sensing
255. Reactances are connected in series: Xc1=100, Xc2=40, XL1=30,
XL2=70. What is the net reactance?
a. 80Xc
c. 60XL
b. 40Xc
d. 50XL
256. A tuned circuit is resonant at 4 MHz. Its Q is 100. What is its
bandwidth?
a. 4 kHz
c. 400 Hz
b. 400 kHz
d. 40 kHz
37
257. What is the value of Rx in kohms to be connected in parallel to
a 75 kohms to reduce the value of total resistance to 10
kohms?
a. 11.7
c. 7.5
b. 15.7
d. 12.7
258. What is the burning hours that should be used in the design
consideration of incandescent bulb?
a. 1,500
c. 850
b. 1,800
d. 650
259. Three capacitors of 3, 4 and 5 microfarads are connected in
series with a 6 volt battery. When the current stops, what is
the voltage across the 3 microfarad capacitor?
a. 1.62 V
c. 2.55 V
b. 1.91 V
d. 1.53 V
260. A transformer rated 2,000 kVA, 34,500/240 volts has 5.75%
impedance. What is the per unit impedance?
a. 0.0636
c. 0.0575
b. 0.0656
d. 34.2
261. It refers to a device that merely boosts a signal and passes it
on.
a. amplifier
c. op – amp
b. booster
d. repeater
262. What do you call an impedance that when a line to ground fault
occurs, produces fault currents that are equal and in – phase?
a. positive sequence
c. negative sequence
b. third sequence
d. zero sequence
263. If 14,000 maxwells emanate from a pole, what must be its area
to have a flux density of 7,000 gauss?
a. 3 cm2
c. 2 cm2
b. 4 cm2
d. 1 cm2
264. In a series or parallel LC circuit, the resonant frequency is
attained when
38
a. Xc is 1/10 of XL
b. XL is 1/10 of XC
c. Power factor angle is 90°
d. Xc = XL
265. A light source has an illumination of 100 footcandles (fc), what
is the illumination in lux?
a. 1,204
c. 1,496
b. 1,075
d. 1,360
266. What is the equivalent of the collector terminal of transistor in
a FET?
a. grid
c. source
b. gate
d. drain
267. What is the percent slip of the synchronous motor when
running?
a. 3
c. 1
b. 2.5
d. 0
268. If you tuned in a FM radio station ranging from 88 MHz to 108
MHz, what is the maximum capacitance in picofarads if L = 0.1
microhenry?
a. 34.5
c. 32.7
b. 38.6
d. 36.8
269. In an induction motor, what is the percent slip if the speed is
3,510?
a. 1
c. 2
b. 1.5
d. 2.5
270. What is the unit of electrical resistance?
a. volt
c. ohm
b. ampere
d. watt
271. Three equal resistors are connected in series. The voltage in
one of the resistors is 15 volts. What is the applied voltage?
a. 30 V
c. 40 V
b. 45 V
d. 50 V
39
272. An ideal full wave rectifier with non inductive load has zero
transformation losses. What is the efficiency?
a. 100
c. 80
b. 90
d. 70
273. A 750 Hp, 2,400 volts three –phase motor has a power factor
90% and efficiency of 95% is to be operated to a 13.2 kV utility
service thru a wye – delta connected transformer. What is the
total kVA of the transformer bank?
a. 575
c. 595
b. 654
d. 615
274. What category do 115 kV – 230 kV belong?
a. low voltage
c. high voltage
b. medium voltage
d. extra high voltage
275. What is the device that converts DC power to AC?
a. converter
c. SCR
b. inverter
d. Rectifier
276. A voltmeter has a resistance of 80 ohms per volt deflection.
What current will flow in milliamperes (mA) when connected
across 150 volt source if it has a 200 volt scale deflection?
a. 11.5
c. 9.4
b. 10.5
d. 12
277. The power drawn by a balanced 3Φ load is 3,000 watts at 80%
power factor. If two wattmeters WA and WC are used, what is
the reading of WC?
a. 800
c. 900
b. 950
d. 850
278. What is the most common cause of failure in cable termination
and splicing? a. tracking
b. poor shielding
c. wrong clearance
d. improper insulation penciling
279. In a series RLC circuit, the resistance is 200 Ω, the inductance
is 10 mH, and the capacitance is 4 µF. If the circuit is connected
across 100 volt source, what is the current?
40
a. 0.144
b. 0.15
c. 0.12
d. 0.13
280. A 3,600 V 500 kVA 60 Hz 3 phase Y – connected generator on
test yields the following results: Mechanical and iron losses is
10 kW; field current at full – load 100% p.f. is 50 A; field
current at full – load 80% p.f. is 70 A; resistance per phase of
armature winding is 0.4 ohm. The exciter voltage is constant
at 120 volts and voltage control is done by means of rheostat.
Determine the full – load armature current at 80% lagging p.f.
a. 95.6 A
c. 64.2 A
b. 99.8 A
d. 80.2 A
281. Three of the following terms in magnetic induction are identical.
Which is distinct among the following?
a. maxwells
c. flux
b. lines
d. gauss
282. One kW-hr is equal to
a. 3,600 watts
b. 1,000 watts
c. 860 k calories
d. 4,186 newtons
283. A power plant is driven by a turbine at a rate of 10 cubic meters
per second and with a head of 235 meters. If the plant
efficiency is 0.65, calculate the power plant output.
a. 10,000 kW
c. 35,000 kW
b. 15,000 kW
d. 25,000 kW
284. At a certain point in a 69 kV transmission line, the positive
sequence impedance is j0.15 p.u., and the zero – sequence
impedance is j0.55 p.u. Calculate the fault current if a line – to
– line fault occurs. The base is 50 MVA.
a. 3,511 amperes
c. 420 amperes
b. 1,890 amperes
d. 2,414 amperes
285. A 3Φ, 220 volt, 10hp induction motor having a power factor of
0.8 has 3% losses. Determine the current drawn by the motor.
a. 25.23 amps
c. 20.18 amps
b. 43.69 amps
d. 14.56 amps
41
286. The three phase unbalanced currents are:
Ia = 10 cis (-30°)
Ib = 0
Ic = 10 cis (150°)
Find the negative sequence current of phase a.
a. 8.66 cis 30
c. -5.77
b. 5.77 cis (-60)
d. 5.77
287. A test is performed on a 230 volts, delta connected
synchronous motor having 92% efficiency and 85% power
factor. With 6 volts dc impressed across its terminals, the
current reading is 90 amperes. Determine the ohmic resistance
per phase.
a. 0.067 Ω
c. 0.1 Ω
b. 0.044 Ω
d. 0.15 Ω
288. A 20 Hp, 110 V dc shunt motor has an efficiency of 88% and
an exciting current of 4 amperes and an armature resistance
of 0.04 ohm. What starting resistance is required for full load
torque?
a. 0.98 Ω
c. 0.95 Ω
b. 0.94 Ω
d. 0.69 Ω
289. A 100 km transmission line has a 1,200 ohms shunt reactance.
What is the per km shunt reactance?
a. 1,200 Ω
c. 12 Ω
b. 120,000 Ω
d. 120 Ω
290. What is the total energy generated by a station in kWHr in a
year if its maximum demand and annual load factor is 150 kW
and 45% respectively?
a. 591,300
c. 24,637
b. 1,314,000
d. 67,500
291. When luminaries direct 90 to 100% of their output downward
is considered a ______.
a. direct lighting
c. indirect lighting
b. local lighting
d. luminaries
42
292. A three phase squirrel cage motor is started by a wye – delta
starter. What shall be its starting torque relative to its rated
voltage starting torque?
a. 33.3%
c. 57.7%
b. 42.3%
d. 100%
293. It took a heater of 2 kW, 158 minutes to raise by 30°C the
temperature of water in an insulated vessel. How many gallons
of water are inside the vessel?
a. 30 gallons
c. 40 gallons
b. 10 gallons
d. 20 gallons
294. A certain shunt motor armature has a resistance of 0.07 Ω and
current of 50 amperes at 120 volts. Determine counter emf.
a. 108.5 V
c. 112.2 V
b. 116.5 V
d. 118.3 V
295. The kH of kWHr meter is 3.2. The disc takes 32 seconds to
complete one (1) revolution. What is the load rating?
a. 0
c. 360 watts
b. 800 watts
d. 2.1 watts
296. In a balanced 3Φ system the phase a voltage is 132.8 cis 0°,
what is the line to line Vca voltage?
a. 230 cis 30°
c. 230 cis (-60°)
b. 230 cis (-30°)
d. 132.8 cis 120°
297. The instantaneous value of the voltage is given by its equation
v = 105 sin ωt – 25 sin 3ωt + 15sin (6ωt- 30°).
What is its rms value?
a. 77 volts
c. 105 volts
b. 190 volts
d. 205 volts
298. A dc shunt motor develops 15 Hp at 120 V. If the effective
armature resistance is 0.061 ohm and the field winding draws
2 amperes, what is the overall efficiency?
a. 90%
c. 95%
b. 93%
d. 94%
299. V12 = 100 cis 30° and V23 = 50 cis 120°. Evaluate V12 - V23.
43
a. 62 cis 6.2°
b. 127.3 cis 40°
c. 111.8 cis 3.4°
d. 62 cis (-6.2)°
300. A 200 microfarad capacitor is connected in series with a 10 Ω
resistor. The circuit is connected to a 24 V battery. What is the
initial current when putting the switch on?
a. 1.2 A
c. 0.255 A
b. 2.4 A
d. 0.0125 A
301. The percent impedance of a line is 6% at 34.5 kV and 100 MVA
base. What is the ohmic impedance?
a. 2.32
c. 0.72
b. 3
d. 1.2
302. The rms value of sinusoidal ac current is equal to its value at
an angle of ___ degree.
a. 60
c. 30
b. 45
d. 90
303. Transformer are rated in kVA instead of kW because
a. load power factor is often not known
b. kva is fixed whereas kw depends on load
c. total transformer loss depends on volt – ampere
d. it has become customary
304. A synchronous motor having 40% reactance and a negligible
resistance is to be operated at rated load unity p.f. If the motor
is rated 100 volts and 100 A, what is the value of induced emf?
Assume delta connected motor.
a. 180 V
c. 4001 V
b. 70 V
d. 108 V
305. The starting winding of a single – phase motor is placed in the
a. rotor
c. armature
b. stator
d. field
306. What is the current per phase in the primary windings of a 3
phase ∆/Y connected 6,600/400 V, 500 kVA, 50 Hz
transformer. Neglect no – load current.
a. 43.74 A
c. 14.58 A
44
b. 75.76 A
d. 25.25 A
307. A 3 Hp 208 volt three phase motor is started by the Y - ∆
method. If the starting current is 54 amp when rated voltage
is applied, what current will flow when the Y - ∆ switch is used?
a. 93.5 A
c. 31.2 A
b. 162 A
d. 18 A
308. An 80:5 current transformer is connected to a 5 amp ammeter.
If the latter registers 3.65 amp, what is the line current?
a. 58.4 A
c. 21.9 A
b. 80 A
d. 3.65 A
309. It is desired to purchase a synchronous condenser to correct
the 2,400 kVA 0.67 lagging p.f. load in an industrial plant to
0.95 lagging. Neglecting losses, calculate the kVA input rating
of the required synchronous condenser.
a. 2,280 kVA
c. 1,500 kVA
b. 1,608 kVA
d. 1,250 kVA
310. The armature of a 230 volt shunt motor has a resistance of
0.18 ohm. If the armature current is not to exceed 76 amp,
calculate the resistance that must be inserted in series with the
armature at the instant of starting. Assume a 2 volt drop at the
brushes.
a. 2.82 Ω
c. 3.18 Ω
b. 3 Ω
d. 2.69 Ω
311. It is desired to step down the three phase voltage from 6,600
to 460 volts using Y - ∆ transformer connection. What should
be the ratio of transformation of each transformer?
a. 1:8.3
c. 1:14.3
b. 14.3:1
d. 8.3:1
312. In a laboratory experiment, the impedance of a coil was
obtained at 60 Hz and 30 Hz. These are 75.48 ohms and 57.44
ohms, respectively. What is the inductance of the coil?
a. 150 mH
c. 42.5 mH
b. 182.5 mH
d. 2.1 mH
45
313. A power customer is applying for source and listed the following
loads:
5 – 15 Hp motors
3 – 5 Hp motors
Lighting loads – 8 kW
Miscellaneous loads 3 – 5 kW
The demand factor is 65%, load factor is 46% and the power
factor is 80%. What is the maximum kW demand of the
customer?
a. 78
c. 69
b. 64
d. 57
314. A 250km transmission line has the following parameters:
resistance per km 0.05 ohm, capacitive reactance per km
625,000 ohms and inductive reactance per km 0.2 ohm. What
is the series impedance?
a. (37.5 + j150) Ω
c. (12.5 + j50) Ω
b. (12.5 – j2,450) Ω
d. (75.5 – j2,450) Ω
315. Combination of switch and fuse.
a. relay
c. fuse cut – out
b. circuit breaker
d. safety switch
316. The phase b voltage and the phase b current of a balanced 3
phase system are: V = 220 sin (ωt + 210°) and I = 10 sin (ωt
- 180°). What is the power of the system?
a. 3,300 W
c. 1,905 W
b. 5,716 W
d. 3,810 W
317. Three similar coils, when connected in delta to a 3 phase, three
wire, 400 volt, 50 Hz supply, take a line current of 7 A at a p.f.
of 0.8 lagging. If the coils are now connected in star to the
same supply, calculate the line current and total power. a. 2.33
A, 3,879 W c. 7 A, 1,293 W
b. 7 A, 3,879 W
d. 2.33 A, 1,293 W
318. Calculate the error in the ammeter which reads 3.25 A in a
circuit having a series standard resistance of 0.01 Ω, the
46
potential difference measured across this standard resistance
being 0.035 V.
a. 7.7%
c. 6.7%
b. 7.1%
d. 5.1%
319. Estimate the distance over which a load of 15,000 kW at 0.85
p.f. can be delivered by a three – phase transmission line
having conductors of steel – cored aluminum each of resistance
0.56 Ω/km. The potential difference at the receiving end is to
be 132 kV and the loss in transmission is not to exceed 7.5%.
a. 122 km
c. 142 km
b. 110 km
d. 150 km
320. An iron ring, 100 cm mean circumference, is made from an iron
rod of round cross – section of 10 cm2. It is wound with 200
turns. What current would be necessary to produce a flux of 1
mWb. Relative permeability of iron = 500.
a. 976 A
c. 796 A
b. 697 A
d. 769 A
321. The force between two wires carrying currents in opposite
directions is 20.4 kg/m when they are placed with their axes 5
cm apart. Calculate the current in one conductor when current
flowing through the other conductor is 5,000 A.
a. 1,000 A
c. 1,500 A
b. 10,000 A
d. 5,000 A
322. Two positive point charges 12 x 10-10 coulomb and 8 x 10-10
coulomb are placed 10 cm apart. Find the work done in bringing
the two charges 4 cm closer.
a. 57.6 x 10-8 J
c. 144 x 10-8 J
b. 14.4 x 10-8 J
d. 5.76 x 10-8 J
323. What is the resonant frequency of a circuit when L is 50
microhenrys and C is 40 picofarads are in parallel?
a. 7.96 MHz
c. 3.56 MHz
b. 79.6 MHz
d. 1.78 MHz
324. Which relay is used for feeders?
a. MHO relay
c. Merz price protection
47
b. Translay relay
d. Buchholz relay
325. A two branch parallel circuit with one branch of R = 50 ohms
and a single unknown element in the other branch has the
following applied voltage and the total current:
v = 100 cos(1500t + 45°) volts
it = 12 sin (1500t + 135°) amperes
Find the unknown element.
a. R = 8.33 Ω
c. L = 10 H
b. R = 10 Ω
d. L = 8.33 H
326. The following information is given for two transformers
connected in parallel and delivering a total load of 300 kVA:
Transformer1
Transformer2
Rating = 150kVA
Rating = 250kVA
6,900/230 volts
6,900/230 volts
Ze – p1 = 9.4 Ω
Ze – p2 = 5.8 Ω
Calculate the load current supplied by each transformer. a.
26.9 A, 16.6 A
c. 734 A, 1190 A
b. 21.7 A, 36.2 A
d. 24.5 A, 39.7 A
327. A 3 phase, 11 kV transmission line 10km long delivers 200 kW
load at 0.8 lagging power factor. The resistance of the line is
0.9 Ω per km per phase. What is the percentage power loss in
the line assuming 11 kV voltage at the receiving end.
a. 1.27%
c. 4.27%
b. 3.27%
d. 2.27%
328. Fusion energy is produced when
a. chemical compounds combined
b. fuel burns
c. nuclear particles divides
d. nuclear particles combined
329. Given Y – connected impedances Za = (2 + j2) Ω, Zb = (5 –
j10) Ω, and Zc = (5 + j10) Ω. Find the equivalent delta
impedance Zbc.
a. (41.22 + j31.23) Ω
c. (30 – j10) Ω
48
b. (41.22 – j31.23) Ω
d. (-10 + j30) Ω
330. One watt – second is also equal to which one?
a. 980 dynes – cm
c. 1 erg – second
b. 1 joule
d. 3 gram – calorie
331. A 115 kV line has a horizontal configuration. The distance
between adjacent conductors is 9 ft. What is the geometric
mean distance of the line?
a. 9 ft
c. 11.34 ft
b. 12 ft
d. 18 ft
332. The total capacitance of two capacitors is 0.03 µF when joined
in series and 0.16 µF when connected in parallel. Find the
capacitance of each capacitor.
a. 0.12 µF, 0.04 µF
c. 0.03 µF, 0.08 µF
b. 0.24 µF, 0.08 µF
d. 0.06 µF, 0.16 µF
333. A hydroelectric plant generates 100 MW at an available head
of 200 m and an overall efficiency of 75%. What quantity of
water in cubic per second is required?
a. 1,200
c. 26
b. 122
d. 68
334. The illumination of a room is being designed. The illumination
intensity required is 50 footcandles. The maintenance factor is
70% and coefficient of utilization is 60%. If the room is 20 ft
by 15 ft, what is the total required lumens output of the lamp?
a. 35,000 lumens
c. 6,300 lumens
b. 10,500 lumens
d. 12,800 lumens
335. One kW is equal to ___ ft-lb/sec.
a. 1,356
c. 1,055
b. 738
d. 550
336. A battery produces a current of 0.6 A when the external
resistance is 2 Ω and 0.2 A when the external resistance is 12
Ω. Find the emf of the battery.
a. 3 V
c. 9 V
b. 6 V
d. 12 V
49
337. An open delta bank delivers a balanced three – phase load of
60 kVA at 460 volts. What current flows in the secondary of
each transformer?
a. 65.2 A
c. 150.6 A
b. 130.4 A
d. 75.3 A
338. The flux density emanating from a pole of a generator is 20,000
gauss. A conductor one meter long cuts the flux perpendicularly
at a speed of 40 m per second. What voltage is developed?
a. 800 volts
c. 230 volts
b. 80 volts
d. 8 volts
339. The capacitive reactance of a 40 km 34.5 kV line is 90,000
ohms per km. What is the total capacitive reactance of the line?
a. 2,250 ohms
c. 6,750 ohms
b. 1.08 x 107 ohms
d. 3.6 x 106 ohms
340. Two voltage generators are in series. The voltages being
generated are Vab = 50 sin (ωt - 30°) and Vbc = 100 sin (ωt +
60°). What is the output voltage Vac?
a. 111.83 cis 33.5°
c. 145.5 cis 50.1°
b. 50 cis 30°
d. 150 cis 30°
341. A lead – acid battery having a 100 A capacity is 25% charged.
After being charged at 10A for 5 hours, it will be approximately
___ charged.
a. 1/2
c. fully
b. 3/4
d. over
342. A current of 1 ampere passes through a relay coil of 500 turns.
What is the mmf?
a. 628 gilberts
c. 9,425 gilberts
b. 943 gilberts
d. 595 gilberts
343. The illumination of a room is being designed from the following
data:
Room length = 40 ft.
Required foot – candle = 200
Room width = 24 ft
Lumens per lamp = 3,300
50
Coefficient of utilization = 0.60 No. of rows = 5
Maintenance factor = 0.70
What is the number of lamps per row?
a. 40
c. 28
b. 35
d. 140
344. What is the tesla a unit of?
a. permittivity
c. permeance
b. capacitance
d. magnetic induction
345. A coil having and inductance of 0.05 H and resistance of 10
ohms is connected in series with a 25 µF capacitor across a 220
V ac source. What is the resonance frequency of the circuit?
a. 77.2 Hz
c. 60 Hz
b. 135.2 Hz
d. 142.4 Hz
346. Two – wattmeter method is applied to a 3 phase motor running
at full – load. Two wattmeters indicate 85.5 kW and 34.7 kW,
respectively. What is the operating power factor of the motor?
a. 87.45%
c. 80.69%
b. 89.49%
d. 94.76%
347. A transmission line consists of two solid aluminum conductors
having a radius of 2.5 cm and separated on centers by a
distance of 3.6 m. Find the total line inductance in millihenrys
per meter.
a. 2.09 x 10-3
c. 0.0209
b. 1.044 x 10-3
d. 0.0104
348. If output power of a radio receiver is doubled, its volume is
increased by _____ db.
a. 2
c. 1
b. 3
d. -3
349. Which of the following methods is used to start a synchronous
motor?
a. resistance starter in the armature circuit
b. damper winding
c. star – delta starter
d. damper winding in conjunction with star – delta starter
51
350. The power factor of an alternator is determined by its ______.
a. speed
c. excitation
b. load
d. prime mover
351. A three – phase induction motor has a nameplate speed of
1,720 rpm. What is the rotor frequency?
a. 4.44 Hz
c. 1.8 Hz
b. 2.7 Hz
d. 5 Hz
352. A 40 microfarad capacitor is connected in parallel with 40 ohm
resistor. What power is drawn when source voltage is V = 220
sin ωt volts?
a. 1825 watts
c. 1210 watts
b. 1010 watts
d. 1620 watts
353. The percentage overloading of two 20 kVA transformers when
supplying a balanced 3 – phase load of 40 kVA in a V – V bank
is ___ percent.
a. 15.5
c. 73.2
b. 57.7
d. 33.3
354. A 3 phase, 3 wire feeder supplies an industrial plant with the
following data:
Line voltages: Vab = 230 0 V, Vbc = 230 240 V
Line currents: Ia = 110 -36.87 A, Ic =125 53.13 A
What is the average power factor of the plant?
a. 0.89 lagging
c. 0.93 leading
b. 0.89 leading
d. 0.93 lagging
355. A 3 phase, 3 wire transmission line has an impedance per wire
of (3 + j7) ohms, the receiving end load is 1,950 kW, 0.65
power factor lagging with line to line voltage of 13,200 volts.
Determine the kVAR of the capacitor to be connected at the
receiving end to make the p.f. at that end equal to 0.8 lagging
at 13,200 volts.
a. 1,482
c. 817
b. 2,280
d. 1,464
52
356. Two 100 watt, 200 volt lamps are connected in series across a
200 volt supply. The total power consumed by each lamp will
be ___ watts.
a. 25
c. 100
b. 50
d. 200
357. A conductor cuts 1 weber of flux per sec. The average voltage
generated in the conductor is _____.
a. 108 mV
c. 100 mV
b. 1000 mV
d. 10 V
358. A 0 – 1 mA meter has a sensitivity of
a. 1mA
c. 1 k
b. 1 k /volt
d. 1000 A
359. For a dc series motor with saturated condition of the field
circuit, the torque developed is proportional to
a. speed
c. Ia2
b. V12
d. Ia
360. A 100 µF capacitor in series w/ a 50 ohm resistance is
connected suddenly across a 125 volt dc supply. What is the
voltage in the capacitor after 5 msec.?
a. 125 V
c. 56.4 V
b. 120 V
d. 79 V
361. The gas inside the inner discharge tube of a sodium vapor lamp
is
a. argon
c. nitrogen
b. neon
d. helium
362. The maximum efficiency of a 100 kVA transformer having iron
loss of 900 watts and full – load copper loss of 1600 watts
occurs at ___ kVA.
a. 56.3
c. 75
b. 133.3
d. 177.7
363. In a 4 - pole, 35 slot, dc armature, 180 electrical degree coil
span will be obtained when coils occupy ___ slots.
a. 1 and 10
c. 2 and 11
53
b. 1 and 9
d. 3 and 13
364. The transients w/c are produced due to sudden but energetic
changes from one steady state of a circuit to another are called
____ transients.
a. initiation
c. transition
b. relaxation
d. subsidence
365. A 13.8 kV/440 V, 50 kVA single phase transformer has a
leakage reactance of 300 ohms referred to the 13.8 kV side.
Determine the per unit value of the leakage reactance for the
low – voltage base.
a. 0.305
c. 0.097
b. 0.0305
d. 0.079
366. While describing the sheath of a cable, the abbreviation XLPE
means ______ polyethylene.
a. cross – layer
c. cross – linked
b. external – layer
d. extra – long
367. Two capacitors of 0.1 µF, 250 V and 0.2 µF, 500 V are
connected in series. What is the maximum voltage that can be
applied across the combination?
a. 375
c. 750
b. 250
d. 500
368. A dc shunt motor draws an armature current of 98.16 A at 120
V. What is the hp output of the motor if the armature effective
resistance is 0.06 ?
a. 15.8
c. 7.5
b. 22
d. 15
369. A non sinusoidal emf having the equation v = 141.4 sin (ωt 60 ) – 56.6 sin (ωt - 30 ) + 35.4 sin (5ωt - 90 ) is impressed
upon a circuit. If the current has the equation I = 28.3 sin (ωt
- 30 ) + 17 sin (3ωt - 90 ), calculate the power factor of the
circuit.
a. 0.857
c. 0.785
b. 0.578
d. 0.958
54
370. A diesel power plant has an overall efficiency of 30%. If the
calorific value of diesel is 18,000 BTU/1b and cost Php6.00 per
liter, how much is the fuel cost of production per kwhr of
energy? Take the density of diesel as 900 grams per liter.
a. Php1.91/kW-hr
c. Php2.12/kW-hr
b. Php1.85/kW-hr
d. Php2.45/kW-hr
371. Two single phase transformers operate in parallel. Transformer
1 is rated 100 kVA with 4% reactance while transformer 2 is
rated 75 kVA with 3% reactance. The transformers have
secondary voltages of 220 volts and same voltage ratio. If the
common load is 125kva at 80% p.f. lagging, determine the kVA
sharing of each transformer.
a. 71.43 kVA & 53.57 kVA
c. 62.5 kVA & 62.5 kVA
b. 75 kVA & 50 kVA
d. 82.5 kVA & 42.5 kVA
372. In a 13.8 kV, 10 MVA base three phase system a phase to
phase fault occurs. If the thevenin‟s equivalent impedance of
the system is 2.63%, what is the magnitude of the fault
current?
a. 13,800 A c. 27,600 A
b. 15,900 A
d. 7,970 A
373. The sequence components of phase a current are:
Ia = 0
Ia1 = (90 + j5.78) A
Ia2 = (10 - j5.78) A
Determine the phase C current.
a. 91.61 131 A
c. 100 120 A
b. 100 0 A
d. 91.61 251 A
374. The CT ratio and PT ratio used to protect a line are 240 and
2000, respectively. If the impedance of each line is 10 , what
is the relay impedance to protect the line from fault?
a. 83.33
c. 48,000
b. 1.2
d. 12
55
375. What is the most probable per unit transient reactance for an
alternator rated 100 MW?
a. 0.02
c. 1.0
b. 0.30
d. 0.1
376. What should be the kV rating of a surge arrester to be used for
an 11 kV ungrounded system?
a. 18 kV
c. 12 kV
b. 16 kV
d. 9 kV
377. A three – phase, 4 – pole induction motor with open – circuited
rotor is connected to a 400 V, 50 Hz, three – phase supply. The
motor will run at ____ rpm.
a. 1500
c. 1450
b. 1480
d. 0
378. What is the self geometric mean distance of a 3 – strand bundle
made of ACSR Rail conductors with 45 cm between conductors?
The GMR of ACSR Rail is 0.0386 ft.
a. 0.4832 ft
c. 0.3842 ft
b. 0.2834 ft
d. 0.4382 ft
379. A 3 phase balanced system working at 0.9 p.f. lagging has a
line loss of 3,600 kW. If p.f. is reduced to 0.6, the line loss
would become _____ kW.
a. 8,100
c. 5,400
b. 1,600
d. 4,800
380. A 55,000 kW thermal power plant of NPC delivers an annual
output of 283,000 MWHr with a peak load of 44 MW. The annual
load factor of the plant is nearest to
a. 0.75
c. 0.76
b. 0.72
d. 0.73
381. For power transformers, the conservator tank is intended to
minimize
a. heating
c. oil slugging
b. internal pressure
d. breathing
56
382. A generator rated 15 MVA, 13.2 kV has 8% impedance is
connected to a step – up transformer of 20 MVA, 13.8/230 kV
for transmission. What is the new per unit impedance using
transformer ratings as base value?
a. 0.146
c. 0.098
b. 0.102
d. 0.107
383. In a vacuum tube, what is the ratio of a small change in plate
voltage to a small change in grid voltage?
a. amplification ratio
c. current ratio
b. voltage ratio
d. amplification factor
384. What is the normal indication on a megger when checking
insulation?
a. one
c. middle of scale
b. infinity
d. zero
385. A flux of 1,500,000 maxwells links a coil having 350 turns. This
flux through the coil is decreased to zero at a uniform rate in
0.2 sec. Determine induced emf during this time interval.
a. 1 volt
c. 26.25 volts
b. 857 volts
d. 8.57 volts
386. What electric power is required to drive a pump which must
raise water 96ft and supply 2,600 gpm? One gallon water
weighs 8.3lbs. motor and pump efficiency are 90% and 70%,
respectively.
a. 46.8 kW
c. 29.5 kW
b. 74.3 kW
d. 60.2 kW
387. The winding of a 4 – pole alternator having 36 slots is short by
2 slots. What is the pitch factor?
a. 0.9397
c. 0.9566
b. 0.9725
d. 1.0
388. The unit of magnetic field intensity in the CGS system is
a. gauss
c. ampere – turn per meter
b. gilbert
d. Oersted
57
389. What is the work done in moving a 50 C electric charge
through a distance of 50cm in the direction of a uniform electric
field of 50 kV/m?
a. 2.5 joules
c. 1.25 joules
b. 500 joules
d. 125 joules
390. A coil with L = 2 H and R = 362 is connected to a 230 V, 50
Hz supply. Calculate the energy stored when the instantaneous
voltage is zero.
a. 0.317 J
c. 0.151 J
b. 0.051 J
d. 0
391. A system is consists of three equal resistors connected in delta
and is fed from a balanced three –phase supply. By how much
power is reduced if one of the resistors is disconnected?
a. 33%
c. 50%
b. 67%
d. 25%
392. A round wire has 250,000 CM. Find its diameter in inches.
a. 1/2
c. 0.16
b. 1/4
d. 0.08
393. One horsepower is equal to _____.
a. 33,000 ft –lb
c. 746 watt –sec
b. 550 ft –lb/sec.
d. 252 cal
394. Which of the following is the most probable impedance of a 100
MW alternator?
a. 5%
c. 10%
b. 100%
d. 20%
395. At a 34.5 kV substation, the available fault current is 10 p.u.
What is the available fault MVA if the base MVA is 50?
a. 50
c. 200
b. 100
d. 500
396. A solenoid has a magnetic reluctance of 2.2 x 10 -3. It has 300
turns. What is the total flux when the current flowing is 0.5
ampere?
58
a. 9.52 x 104
b. 9.82 x 104
c. 8.57 x 104
d. 9.12 x 104
397. The instantaneous value of the voltage is given by the equation
e = 105 sin ωt – 25 sin (3ωt + 60°) + 15 sin (6ωt + 30°). Find
its rms value.
a. 77 volts
c. 190 volts
b. 105 volts
d. 205 volts
398. A dc shunt motor develops 15 Hp at 120 V. If the effective
armature resistance is 0.061 ohm and the field winding draws
2 amperes, what is the overall efficiency?
a. 90%
c. 95%
b. 93%
d. 94%
399. A voltage wave is given by v = 100 sin 314t. How long does it
take this waveform to complete one – fourth cycle?
a. 20ms
c. 5 ms
b. 10 ms
d. 1 ms
400. An ac voltage (100 + j60) volts is applied to a circuit and the
current so produced is (-4 + j10) amperes. The power
consumed by the circuit is
a. -400 W
c. 200 W
b. 100 W
d. 500 W
401. The voltages across two series connected circuit elements are
V1 = 50 sin ωt volts and V2 = 30 sin (ωt - 30°) volts. What is
the rms value of the applied voltage?
a. 54.77 V
c. 56.57 V
b. 80 V
d. none of the above
402. A 240 V, 50 Hz series RC circuit takes an RMS current of 20
amperes. The maximum value of the current occurs 1/900
second before the maximum value of the voltage. The p.f. of
the circuit is
a. 0.92
c. 0.866
b. 0.94
d. 0.8
59
403. A series RL circuit has the following data:
R = 10 ohms
L = 0.02 H
e = 150 + 100 sin ωt + 50 sin 3 ωt volts w
= 500 rad/sec
t – time, seconds
What is the average power of the circuit?
a. 2875 watts
c. 2645 watts
b. 2350 watts
d. 2512 watts
404. A circuit which has Wo = 106 rad/sec, C = 10 pF and Q – factor
of 100, must have a resistance of ____ kohm
a. 10
c. 1
b. 5
d. 100
405. A hydroelectric plant generates 100 MW at an available head
of 200 m at an overall efficiency of 75%. What quantity of
water in cubic meter per second is required?
a. 68
c. 122
b. 1200
d. 26
406. A 100 liter of water is heated from 20°C to 40°C. How many
kWHr of electricity is needed assuming no heat loss?
a. 4.2
c. 5.6
b. 2.3
d. 3.7
407. A generator has an output of 10 kW. What is its output in joules
per sec?
a. 10,000
c. 80,000
b. 100,000
d. 1,000
408. The difference between the front pitch and the back pitch of a
retrogressive lap winding is 2. If the front pitch is 21, what is
the back pitch?
a. 19
c. 21
b. 23
d. 21.5
409. The transformer used to serve a customer is rated 5 MVA, 13.8
kV/480 V and its impedance is 5%. The cable connecting the
breaker to the transformer has an impedance of 0.032 ohm per
60
phase. What is the fault current if a three phase fault occurs at
the breaker?
a. 8000 A
c. 6000 A
b. 5000 A
d. 1200 A
410. V12 = 100 cis 30° and V23 = 50 cis 120°. Evaluate V12 - V23.
a. 62 cis 6.2°
c. 111.8 cis 3.4°
b. 127.3 cis 40°
d. 62 cis (-6.2°)
411. A 5 mH pure inductance is connected in parallel with one µF
capacitor. What frequency shall the circuit be in antiresonance?
a. 250 Hz
c. 60 Hz
b. 2250 Hz
d. 100 Hz
412. A 200 microfarad capacitor is connected in series with 10 Ω
resistor. The circuit is connected to a 24 V battery. What is the
initial current when putting the switch on?
a. 1.2 A
c. 0.225 A
b. 2.4 A
d. 0.0125 A
413. A 115 kV line has vertical configuration with 9 ft spacing. The
diameter of the 336.4 ACSR is 0.721 inch. What is the total
capacitance if the length of the line is 20 km?
a. 0.282 µF
c. 2.2 µF
b. 0.187 µF
d. 5.25 µF
414. In a certain circuit analysis, the bases chosen are 34.5 kV and
100 MVA. What is the base impedance?
a. 11.9 Ω
c. 23.8 Ω
b. 7.5 Ω
d. 5 Ω
415. The percent impedance of a line is 6% at 34.5 kV and 100 MVA
base. What is the ohmic impedance?
a. 2.32
c. 0.72
b. 3
d. 1.2
416. A 69 kV/13.8 kV, 7.5 MVA transformer has 8% impedance.
What is its impedance at 100 MVA base?
a. 0.6%
c. 800%
b. 8%
d. 106.7%
61
417. A 50 MW coal – fired power plant has an average heat rate of
11,000 BTU per kWHr. Coal has a heating value of 13,000 BTU
per pound. The plant has a load factor of 80%. How much coal
is burned per day?
a. 8.2 x 106 lb
c. 1.2 x 105 lb
b. 7.2 x 106 lb
d. 8.1 x 105 lb
418. A dc current of 50 amperes flows through a long straight
conductor. Determine the force on a magnetic pole of 50 unit
pole strength placed 5 cm from the conductor.
a. 100 dynes
c. 100∏ dynes
b. 1000 dynes
d. 200 dynes
419. The load on a three phase wye connected 220 V system
consists of three 6 Ω resistances connected in wye and in
parallel with three 9 Ω resistance connected in delta. The
magnitude of the line current is
a. 36.66 A
c. 42.34 A
b. 24.44 A
d. 63.50 A
420. On a symmetrical 3Ф system, phase sequence ABC, a
capacitive reactance of 8 Ω is connected across BC, and a coil
R + jXL across AB. Find R and XL such that IB = 0.
a. 4 Ω & 6.93 Ω
c. 6.93 Ω & 4 Ω
b. 69.3 Ω & 4 Ω
d. 4 Ω & 69.3 Ω
421. Three unbalanced 3Ф line voltages are given as follows:
VA = 10 cis 30°
VB = 30 cis (-60°)
VC = 15 cis 145°
What is the negative sequence component of line voltage VC?
a. 8.24 cis (-156.2°)
c. 8.24 cis (-276.2°)
b. 8.24 cis (-36.2°)
d. 0
422. A 350 kW, 2,300 V, three – phase resistive load is measured
with two small watt – meters. Two 100/5 A current
transformers and two 2,300/115 V potential transformers
makes this possible. The reading of each wattmeter in watts is
62
a. 505
b. 437
c. 450
d. 473
423. A 440 V, 70 Hp shunt motor has an armature of 0.185 Ω and
field resistance of 350 Ω. The current drawn by this machine is
135 A at full load. If this machine is to deliver torque equal to
175 percent of that at full – load, what would be the resistance
of its starter?
a. 2 Ω
c. 1.695 Ω
b. 1.2 Ω
d. 5.6 Ω
63
424. The flux density emanating from a pole of a generator is 20,000
gauss. A conductor one meter long cuts the flux perpendicularly
at a speed of 40 m per second. What voltage is developed?
a. 800 volts
c. 230 volts
b. 80 volts
d. 8 volts
425. The resistance of the field winding of a dc machine is 0.25 Ω at
25°C. When operating at full –load, the temperature of the
winding is 75°C. The temperature coefficient of resistance of
copper is 0.00427/°C at 0°C. Find the resistance of the field
winding at full –load.
a. 0.298 Ω
c. 0.512 Ω
b. 0.315 Ω
d. 0.271 Ω
426. The capacitive reactance of a 40 km 34.5 kV line is 90,000
ohms per km. What is total capacitive reactance of the line?
a. 2250 Ω
c. 6750 Ω
7
b. 1.08 x 10 Ω
d. 3.6 x 106 Ω
427. Three unbalanced 3Ф line currents are:
Ia = 10 cis (-30°)
Ib = 0
Ic = 10 cis (150°)
What is the phase b positive sequence current?
a. 8.66
c. 5.77
b. 5.77 cis 240°
d. 8.66 cis 120°
428. A certain generator generates 1,500,000 joules per minute.
What is the output in kW?
a. 50
c. 25
b. 500
d. 125
429. A 3 phase bank serves four customers with the following loads:
Customer A = 80 kW at 65% p.f.
Customer B = 60 kW at 85% p.f.
Customer C = 100 kW at 90% p.f.
Customer D = 120 kW at 70% p.f.
a.
b.
64
What is the equivalent power factor?
82.16%
c. 76.66%
79.21%
d. 84.37%
430. A 5 km long, three phase 34.5 kV line has a horizontal
configuration of 4 ft spacing. The conductors are 336.4 ACSR
with GMR of 0.0244 ft. What is the inductance of the line?
a. 5.33 mH
c. 10.22 mH
b. 15.12 mH
d. 12.02 mH
431. Two voltage generators are in series. The voltages being
generated are Vab = 50 sin (ωt - 30°) and Vbc = 100 sin (ωt +
60°). What is the output voltage Vac?
a. 111.83 cis 33.5°
c. 145.5 cis 50.1°
b. 50 cis 30°
d. 150 cis 30°
432. A short 230 kV transmission line has an impedance of 5 cis 78°
ohms. The sending end power is 100 MW at 230 kV and 85%
power factor. What is the line loss?
a. 1.21 MW
c. 962 kW
b. 728 kW
d. 272 kW
433. A 25 kVA, 550/220 V transformer has a rated copper loss of
350 watts. With the low voltage winding shorted it requires 25
V across the high voltage winding to permit rated current
through both windings of the transformer. The percent
reactance of the transformer is
a. 5.72
c. 4.54
b. 1.4
d. 4.32
434. A 5,000 kVA transformer has a rated copper loss of 30,118
watts. The maximum demand on the bank within the past year
was 81% of the rated capacity and the loss factor was 26.75%.
What was the total annual copper energy loss in the bank?
a. 57,120 kW-Hr
c. 46,300 kW-Hr
b. 213,700 kW-Hr
d. 173,000 kW-Hr
435. Three, 1Ф, 75 kVA transformers are banked in delta supplying
a balanced three –phase load of 160 kVA at 0.8 p.f. lagging. If
65
one transformer is removed for repair, what is the minimum
amount in kVAR of capacitor bank needed to prevent the
overloading of the remaining units?
a. 86.73
c. 63.78
b. 96
d. 73.86
436. A 6 pole, 50 Hz, three phase induction motor is running at 950
rpm and has a rotor copper loss of 5 kW. The rotor input in kW
is
a. 100
c. 95
b. 105
d. 110
437. A synchronous motor absorbing 60 kW is connected in parallel
with a load of 240 kW having a lagging p.f. of 0.8. If the
combined load has a p.f. of 0.9 lagging, what is the value of
the leading kVAR supplied by the motor?
a. 145.4
c. 17.3
b. 180
d. 34.6
438. A 60 Hz, three phase 100 mile transmission line draws a
charging current of 0.5 A per mile when the line is tested at
100,000 V to neutral. The total capacitive susceptance of the
line is nearest to
a. 5 x 10-4 mho
c. 5 x 10-6 mho
b. 8.66x 10-4 mho
d. 2.9 x 10-4 mho
439. A three phase, 11 kV transmission line is 10 km long and
delivers 200 kW load at 0.8 lagging power factor. The
resistance of the line is 0.9 ohm per km per phase. What is the
percentage power loss in the line assuming 11 kV voltage at
the receiving end?
a. 2.27%
c. 4.27%
b. 3.27%
d. 5.27%
440. A generating station has a maximum load of 20 MW for the
year and the maximum loads on the substations are 7.5 MW,
6 MW, 5.5 MW and 4.5 MW. The diversity factor is
a. 1
c. 1.175
a.
b.
66
b. 1.5
d. 1.75
441. A room 8 m x 12 m is lighted by 15 lamps to fairly uniform
illumination of 100 lumens per sq. meter. What is the
coefficient of utilization if the output of each lamp is 1,600
lumens?
a. 30%
c. 50%
b. 40%
d. 60%
442. One hundred kW is equivalent to ____ joules/second.
100
c. 10,000
1,000
d. 100,000
443. Capacitors are said to
a. block AC and pass DC
b. block DC and pass AC
c. pass AC and DC
d. block AC and DC
444. When a high voltage AC circuit breaker is tested for
endurance, it is tested for at least ___
a. 1,000
c. 10
b. 100
d. 5
445. The number of cycles in which a high speed circuit breaker can
complete its operation is
a. 3 to 8
c. 20 to 30
b. 10 to 18
d. 40 to 50
446. A graphical representation between discharge and time is
known as ___
a. monograph
c. hydrograph
b. hectograph
d. topograph
447. One volt is equal to ___ abvolts.
a. 106
c. 108
b. 1,000
d. 10-2
67
448. A fully – charged lead – acid cell has an open circuit voltage of
about ____ volt.
a. 2.1
c. 2.3
b. 2.2
d. 2.5
449. Which of the following is not a standard distribution voltage?
a. 6.24 kV
c. 13.8 kV
b. 16 kV
d. 11 kV
450. What is the total capacitance of two 20 µF capacitors in series?
a. 40 µF
c. 40 pF
b. 10 µF
d. 10 pF
451. The fuse used for the overhead primary distributors is
a. cartridge
c. expulsion
b. dual element
d. fast acting
452. The power required to produced a gain of 10 dB over 4 watts
of original power is ___ watts.
a. 80
c. 0.4
b. 40
d. 8
453. A type of motor that overspeed at a very light load.
a. shunt
c. flat – compound
b. over – compound
d. series
454. What is the most probable per unit transient reactance for an
alternator rated 100 MW?
a. 0.02
c. 1.0
b. 0.3
d. 0.1
455. What should be the kV rating of a surge arrester to be used for
an 11 kV ungrounded system?
a. 18 kV
c. 12 kV
b. 16 kV
d. 9 kV
a.
b.
68
456. Which of the following source of energy is not commercially
used?
a. wind
c. geothermal
b. solar
d. biogas
457. If the stator voltage of a SCIM is reduced to 50 percent of its
rated value, torque developed is reduced by ___ percent of its
full – load value.
a. 50
c. 57.7
b. 25
d. 75
458. Two 60 Hz induction motors are connected in concatenation
(cascaded). If machine 1 has 6 poles and machine 2 has 8
poles, the speed of the combination when the slip is 0.075 is
___ rpm.
a. 514
c. 3,600
b. 475
d. 1,110
459. A power station supplies 60 kW to a load over 2,500 ft of 000
2 – conductor copper feeder the resistance of which is 0.078
ohm per 1,000 ft. The bus – bar voltage is maintained constant
at 600 volts. Determine the maximum power which can be
transmitted.
60 kW
c. 120 kW
230.7 kW
d. 150 kW
460. Three units of 1:5 transformers are connected in ∆/Y to supply
three – phase load from a 400 volt, three – phase source. The
line voltage on the load side is ___ volts.
a. 2,000
c. 3,464
b. 80
d. 80 3
461. Neglecting saturation, if current taken by a series motor is
increased from 10 A to 12 A, the percentage increase in its
torque is ___ percent.
a. 20
c. 30.5
b. 44
d. 16.6
462. Out of the following given choices for polyphase transformer
connections, which one will you select for three to two phase
conversion?
69
a. Scott
b. star/star
c. double Scott
d. star/double – delta
463. Two currents i1 and i2 whose values are given by the
expressions i1 = 20 sin ωt and i2 = 15 sin (ωt + ∏/4) are
combined and made to pass through the common conductor. If
the circuit has a resistance of 12 Ω, what will be the total
energy loss in 10 hours?
a. 62.929 x 103 J
c. 2.646 x 108 J
b. 2.266 x 108 J
d. 26.46 x 108 J
464. For power transformers, the conservator tank is intended to
minimize
a. heating
c. oil slugging
b. internal pressure
d. breathing
465. As referred to the Proposed Omnibus Power Act, IPP stands for:
a. Internal Power Plant
b. Individual Power Plants
c. Individual Power Protectors
d. Individual Power Producer
466. The PTR and CTR used to protect a line are 2,000 and 240,
respectively. If the reactance as seen on the relay side is 1.41
Ω, what is the reactance of each line?
a. 12.2 Ω
c. 14 Ω
b. 11.75 Ω
d.16 Ω
a.
b.
70
467. When a bird lands on transmission lines, it is not electricuted
because
a. no potential difference
b. bird‟s feet has high dielectric
c. no path for electric flow
d. bird‟s feather is an insulation
468. In a 10:1 step – down, 2200/220 V transformer, taps are
changed to reduce the number of primary turns by 5%. The
secondary voltage will most nearly be ___ volts.
a. 209
c. 240
b. 231
d. 225
469. A three –phase, 4 pole induction motor with open – circuited
rotor is connected to a 400 V, 50 Hz, three – phase supply.
The motor will run at ___ rpm.
a. 1500
c. 1450
b. 1480
d. 0
470. The starting torque of a capacitor – start split phase induction
motor is directly related to the angle
between its two –
winding currents by the relation
a. cos
c. tan
b. sin
d. sin /2
471. A certain four – terminal transmission device has a
characteristic impedance of 600 ohms and a propagation
constant of 0.5 + j1.0. When terminated with its
characteristic impedance, the ratio of the input voltage to the
output voltage is what?
a. 1.5
c. 0.5
b. 1.65
d. 1.0
472. The line currents in a three – phase four – wire system are Ia
= (300 + j400) A, Ib = (200 + j200) A and Ic = (-400 – j200)
A. Determine the positive sequence component of Ia.
a. 276 25.6° A
c. 276 265.6° A
b. 276 145.6° A
d. 0
71
473. A system is consists of three equal resistors connected in delta
and is fed from a balanced 3 – phase supply. By how much
power is reduced if one of the resistors is disconnected?
a. 33%
c. 50%
67%
d. 25%
474. A balanced wye – connected load consisting of ZY = (3 + j4)
Ω/phase and a balanced delta – connected load having ZA = (9
+ j12) Ω/phase are connected to a 220 V three – phase source.
On a per – phase basis, calculate the line current Ia.
a. 50.8 53.13 A
c. 5.08 173.13 A
b. 50.8 173.13
A
d. 5.08
53.13
A
475. The load on a three phase wye connected 220 V system
consists of three 6 Ω resistance connected in wye and in parallel
with three 9 Ω resistance connected in delta. The magnitude of
the line current is
a. 36.66 A
c. 42.34 A
b. 24.44 A
d. 63.50 A
476. The apparent power input to a balanced wye – connected load
is 30 kVA, and the corresponding true power is 15 kW at 50
A. The phase voltage is
a. 346.4 V
c. 230 V
b. 400 V
d. 200 V
477. Two purely resistive loads are connected to a 240 V three –
phase, 3 – wire balanced supply. One of 4 kW is connected
across lines A and B and the other of 6 kW is connected across
lines B and C. The current in line B is
a. 14.67 A
c. 36.3 A
b. 8.33 A
d. 41.67 A
478. Three unbalanced 3Φ line voltages are given as follows:
VA = 10 cis 30
VB = 30 cis (-60 )
VC = 15 cis 145
b.
72
What is the negative sequence component of line voltage VC?
a. 8.24 cis (-156.2 )
c. 8.24 cis (-276.2 )
b. 8.24 cis (-36.2 )
d. 0
479. A 440 V, 70 Hp shunt motor has an armature of 0.185 Ω and
field resistance of 350 Ω. The current drawn by this machine is
135 A at full load. If this machine is to deliver torque equal to
175 per cent of that at full – load, what would be the resistance
of its starter?
a. 2 Ω
c. 1.695 Ω
b. 1.2 Ω
d. 5.6 Ω
480. The initial rate of current rise in an RL circuit is 300 A/sec when
120 V is suddenly impressed. If the circuit resistance is 30 Ω,
what is the rate of current change when the current is 2.6 A?
a. 300 A/sec
c. 10 A/sec
b. 105 A/sec
d. 0.4 A/sec
481. A 230 V single phase meter has a constant load current of 4 A
passing through the meter for 5 hours at unity power factor. If
the meter disc makes 1,104 revolutions during this period, the
meter constant in revolutions per kW-Hr is
a. 240
c. 480
b. 120
d. 360
482. The armature of a dc machine having 10 poles is rotating at a
speed of 10 revolutions per second. The number of hysteresis
loops formed per second is
a. 100
c. 150
b. 10
d. 50
483. A 5:1 ratio ideal transformer has a rated primary line voltage
of 230 V. If a load impedance of 4 Ω is connected across the
secondary, what will be the primary impedance?
a. 20 Ω
c. 1.25 Ω
b. 100 Ω
d. 80 Ω
73
484. A 500 kVA, 13,200/240 V, three – phase transformer with an
impedance of 4.2% is connected to an infinite bus and without
load. If a three – phase fault occurs at the secondary terminals,
the fault current in amperes is
a. 26,040 A
c. 24,680 A
b. 26,840 A
d. 28,640 A
485. A 3 phase balanced system working at 0.9 p.f. lagging has a
line loss of 3,600 kW. If p.f. is reduced to 0.6, the line loss
would become ___ kW.
a. 8,100
c. 5,400
b. 1,600
d. 4,800
486. A single transmission line has an impedance of (2 + j5) Ω
supplies a load of 50 kW at unity p.f. Find the voltage at the
receiving end if the sending end is 2,400 volts.
a. 2,300 V
c. 2,225 V
2,400 V
d. 2,375 V
487. A 55,000 kW thermal power plant of NPC delivers an annual
output of 283,000 MWHr with a peak load of 44 MW. The annual
load factor of the plant is nearest to
a. 0.75
c. 0.76
b. 0.72
d. 0.73
488. If a generating station has a maximum load for the year of
18,000 kW and a load factor of 30.5%, how many units are
generated for the year?
a. 5,490,000 kW-Hr
c. 59,016,000 kW-Hr
b. 48,092,400 kW-Hr
d. 4,590,000 kW-Hr
489. Presence of ozone as a result of corona is harmful because
a. it gives bad odor
b. it transfers energy to the ground
c. it reduces power factor
d. it corrodes the material
b.
74
490. Two 1 , 25 kVA transformer are connected in open – delta
bank. Determine the maximum kW the bank can supply
without overloading at 0.8 p.f. lagging
a. 43.3
c. 40
b. 34.64
d. 50
491. Two impedances given by Z1 = (10 + j5) and Z2 = (8 + j6)
are joined in parallel and connected across a voltage of V =
(200 + j0) V. What is the circuit power?
a. 6,400 W
c. 1,600 W
b. 3,200 W
d. 800 W
492. A distributor is designed from the point of view of
a. voltage drop
b. current carrying capacity
c. voltage drop and current carrying capacity
d. load capacity
493. The luminous intensity is defined as
a. lumen per square meter
b. luminous flux per unit solid angle
c. illumination per square meter
d. candela per unit solid angle
494. MHO relay is used for
a. rectifier
b. circuit breakers
c. transmission lines
d. feeders
495. In circuit breaker the time duration from the instant of fault to
the instant of energizing of the trip coil is known as
a. lag time
c. protection time
b. lead time
d. operation time
496. Twenty tons of water are heated in 12 hours. If water is to be
heated from 25 C to 95 C, find the kW rating of the heater if
its efficiency is 92%.
75
a. 147
b. 136
c. 163
d. 174
497. What is the generated voltage in a 6 pole, 1200 rpm machine
if its lap wound armature has 8 conductors in each of its 126
slots and a flux density of 57,000 lines per square inch exists
over each pole face of 52.2 square inch?
a. 60 V
c. 300 V
b. 120 V
d. 600 V
498. A capacitor is charged by a steady current of 0.0012 amp for
25 sec. at which time its emf is 600 volts. What is the energy
stored in the capacitor?
a. 6 joules
c. 9 joules
b. 3 joules
d. 12 joules
499. What is the output current in amperes corresponding to
maximum efficiency for a transformer having core loss of 100
watts and equivalent resistance referred to the secondary of
0.25 ?
a. 40 A
c. 20 A
b. 80 A
d. 4 A
500. In
a.
b.
c.
d.
transformer, the purpose of breather is to:
extract moisture of the air
to take insulating oil from conservator
to provide cooling to the winding
to provide insulation to the winding
501. What is the common unit of the sound absorption coefficient?
a. watt
c. sabine erg
d. decibel 502. The maximum power
developed in a synchronous motor
occurs at a coupling angle of
a. 0
c. 90
b. 45
d. 180
b.
76
503. The dc armature winding resistance between terminals of a 750
kVA, 4400 volt, three – phase alternator is 0.9 ohm.
Calculate the copper loss in the winding at the full –load.
a. 13,075 W
c. 26,149 W
b. 16,343 W
d. 10,800 W
504. It is also known as the polar graph of intensities of
illumination
a. Photometric brightness
b. Photosensor
c. Photometric report
d. Photometric distribution
505. What is the frequency range of the electrical equipment used
to melt metals without the use of bunker fuel oil for induction
heating?
a. 500 – 1000 Hz
c. 1 – 20 kHz
b. 50 – 100 kHz
d. 100 – 200 kHz
506. In a series motor, what is the
motor field winding with respect
a. series
b. parallel
relation of the connection of
to the motor armature?
c. series – parallel
d. delta
507. If three transformers in - are delivering rated load and one
transformer is removed, then what is the overload on each of
the remaining transformer in percent?
a. 173%
c. 57.7%
b. 73.3%
d. 33.3%
508. A 6 pole, 60 Hz, 1140 rpm induction motor has a starting
voltage of 120 volts across its rotor winding. What is its starting
current in amperes if the rotor resistance is 5 and its blocked
rotor reactance is 10 ?
a. 24
c. 9.7
b. 10.7
d. 12
77
509. What is the minimum number of magnetic contactors to allow
forward – reverse control in the rotation of a motor?
a. 4
c. 2
b. 3
d. 1
510. What is the short – circuit temperature rating of cross –linked
polyethylene (XLPE) cable in C?
a. 150
c. 250
b. 200
d. 300
511. What is the element of the transmission line that supports the
cable at the bottom of the suspension insulator?
a. parallel clamp
c. dead end clamp
b. suspension clamp
d. strain clamp
512. The field circuit of a 4 pole dc generator has a resistance of 200
and an inductance of 100 H. If it is connected to a 400
volt supply, find the time taken for the current to reach 1.5 A
a. 0.125 sec.
c. 0.369 sec.
b. 1.5 sec.
d. 0.693 sec.
513. Calculate the effective voltage in one phase of an alternator,
given the following particulars: f = 60 cps; turns per phase N
= 240; flux per pole = 2.08 x 106.
a. 1,330 V
c. 1,225 V
b. 2,304 V
d. 2,122 V
514. When a circuit breaker is selected for a particular application,
which one of the following ratings is usually considered the
most important?
a. interrupting rating
b. continuous current rating
c. maximum rms current up to 1 second
d. maximum rms current up to 4 seconds
78
515. Which one of the following switchgear assemblies would most
probably be used in a large industrial plant having several 600
volt meters, an air-conditioning system, and an extensive
lighting system?
a. a low-voltage metal-enclosed switchgear
b. switchgear with SF6 circuit breakers
c. a station-type switchgear
d. a metal-clad switchgear
516. Periodic tests on protective relays are important to the stability
of a system because the tests ensure that the: a. disconnect
switches will work properly
b. “in” and “out” currents will be balanced
c. relays will operate in the proper sequence
d. arcing contacts can carry the main currents
517. If a fault occurs on substation high-voltage bus, the system is
protected by a:
a. generator breaker
b. station feeder breaker
c. low-voltage power transformer breaker
d. high-voltage power transformer breaker
518. Which one of the following tests is preferred for checking
switchgear insulation?
a. an arc high potential test
b. a dc high potential test
c. megometer test
d. a power factor test
519. In generating and distribution system, current balance is
provided by protective zones which are:
a. used to eliminate reflections on short transmission lines
b. used to trip all circuit breakers I the system
c. isolated during fault by disconnect switches
d. monitored by differential relays
520. In switchgear application, the term “dead front” means that:
a. the front and rear panels are hinged
79
b. an access door is at the end of the structure
c. no equipment is mounted on the front panel
d. energized parts are not exposed on the front panel
521. The power flow between two electrical systems connected by
tie lines is stabilized by the difference between:
a. voltage magnitude
c. phase angles
b. current magnitude
d. bearing temperatures
522. A circuit breaker that can be closed against a fault and operated
at once, although the solenoid mechanism may continue
through its closing operation, is said to be:
a. selective
c. fully-rated
b. trip-free
d. direct current operated
523. A large electric power distribution system is protected against
surges and faults by:
a. protective gaps crossing drain coils
b. high-speed relays detecting the trouble
c. protective relays operating without a time delay
d. radio communication systems using flow frequency
524. If a 15-kV switchgear apparatus is used at an altitude of 1500
meters, the maximum applied voltage should be:
a. 4900 volts
c. 4750 volts
b. 4800 volts
d. 4000 volts
525. Which of the following steps is used for isolating a circuit
breaker for maintenance purposes: a. pull the substation fuses
b. turn off the main generator
c. open the disconnect switches
d. ground the auxiliary
526. It is the reciprocal of the impedance:
a. conductance
c. reactance
b. susceptance
d. admittance
80
527. The impedance which when connected to one pair of terminals
of a transducer produces a like impedance at the other pair of
terminals:
a. characteristics impedance
c. iterative impedance
b. input impedance
d. surge impedance
528. In
a.
b.
c.
d.
series circuit, resonance is defined as a condition which:
the net reactance to zero
total voltage is in phase with the current
the power factor is unity
all of the above
529. The product of the total voltage to the total current is:
a. total power
c. reactive power
b. real power
d. apparent power
530. In series RLC circuit at resonance, the current is:
a. zero
c. maximum
b. minimum
d. unity
531. In a variable resistant constant RL series circuit, the locus of
the current is a:
a. straight line
c. ellipse
b. parabola
d. semi-circle
532. The Norton‟s equivalent circuit is a:
a. series circuit
c. series-parallel circuit
b. parallel circuit
d. parallel-series circuit
533. In any network of linear-bilateral impedances, a shift of source
voltage E from one point in a circuit to a second is accompanied
by a corresponding shift of current 1 from the second point to
the first. This is known as:
a. Kirchhoff‟s laws
c. Thevenin‟s theorem
b. Norton‟s theorem
d. Reciprocity theorem
534. In a T method of measuring power in balanced 3-phase system
using one wattmeter, total power is the wattmeter deflection
multiplied by:
81
a. 1
b. 2
c. 1.732
d. 1.5
535. In the current transformer method of measuring power in
balanced 3-phase system one wattmeter, total power is the
wattmeter deflection multiplied by:
a. 1
c. 1.732
b. 2
d. 1.5
536. The order of rotation f the coil voltage in a balanced 3-phase
system is called:
a. alternation
c. phase shift
b. frequency
d. phase sequence
537. A balanced two-phase system of voltages consists of two
voltage which are equal and out of phase by:
a. 30 degrees
c. 120 degrees
b. 90 degrees
d. 150 degrees
538. In a 3-phase synchronous converter, the ratio of the ac voltage
to dc voltage is:
a. 1.0
c. 0.612
b. 0.707
d. 0.50
539. A non-sinusoidal wave is symmetrical if it is made up only of:
a. dc component
c. even harmonics
b. triangular wave
d. odd harmonics
540. An exchange of conductor positions in transmission line is
called:
a. alternation
c. transposition
b. bundling
d. interpolation
541. A line terminal in its characteristic or surge impedance is called:
a. incident line
c. attenuated line
b. reflected line
d. flat line
82
542. The total input to the armature at no load minus the armature
resistance loss is:
a. power developed in the armature
b. stray load
c. stray power
d. shunt field loss
543. It is the power required to drive the unexcited dc machine at
normal speed with its brushes lifted: a. Friction and windage
loss
b. Brush friction loss
c. Exciter loss
d. Ventilation loss
544. When a circular breaker is selected for a particular application,
which one of the particular ratings is usually considered most
important?
a. interrupting rating
c. momentary rating
b. continuous rating
d. maximum current rating
545. In starting a 500hp, 2300 volt, 3-phase synchronous motor the
field winding is initiallly short circuited so as to: a. produce
much larger starting torque
b. lower voltage produced between layers of the field winding
c. increased induced voltage in field winding
d. provide better flux distribution in the air gap
546. The ratio of the average load on the plant for the period of time
to the aggregate rating of all generating equipment: a. plant
use factor c. power factor
b. capacity factor
d. maintenance factor
547. The ratio of the individual maximum demands of the systems
to the overall maximum demand of the whole system: a. load
factor
c. utilization factor
b. diversity factor
d. demand factor
83
548. In parallel operation of alternators, if the excitation of one
alternate is changed it will only change: a. real power taken by
the machine
b. reactive power taken by the machine
c. apparent power taken by the machine
d. synchronizing power of the machine
549. In a medium or long line when operated at no load or loaded
very slightly, the receiving end will be found greater than the
sending end voltage. This phenomenon is known as:
a. Skin effect
c. corona
b. Ferranti effect
d. Thevenin‟s theorem
550. For parallel operation of dc generators:
a. the frequency must be the same
b. the voltage must be the same
c. phase sequence must be the same
d. speed must be the same
551. The simplest form of motor controller is:
a. toggle switch
c. manual starter
b. magnetic switch
d. magnetic control
552. Another name for the magnetic starter is a:
a. manual switch
c. manual starter
b. contactor
d. magnetic control
553. A 15A fuse is found open, but the services do not have a
replacement and has a choice between a 10A and 30 A fuse.
Use the:
a. 10A fuse
c. 40A fuse
b. 30A fuse
d. 20A fuse
554. What type of overload contains a solder pot?
a. melting alloy
c. magnetic
b. bimetallic
d. fuse
84
555. What type of overload operates on the
electromagnetism?
a. melting alloy
c. magnetic
b. bimetallic
d. fuse
principle
of
556. Low voltage often causes the magnetic control to:
a. gum up
c. chatter
b. run more efficiently
d. none of the above
557. Rapid stopping of a motor by momentarily connecting the
motor in reverse direction is called:
a. togging
c. plugging
b. inching
d. sequence operation
558. A hot smokey transformer indicates a/an
a. open
c. both (a) and (b)
b. short
d. none of the above
559. A sorted motor will draw _____ current
a. low
c. both (a) and (b)
b. high
d. none of the above
560. 3-phase manual-starting switches are sometimes used to turn
on or off motors up to ______ horsepowers.
a. 5
c. 15
b. 10
d. 20
561. The device used to control a motor from a distant location is
the:
a. manual starter
c. magnetic controller
b. drum switch
d. snap switch
562. Which of the following devices is a type of timer?
a. interval
c. percentage
b. pulse
d. all of the above
563. The device that controls the flow of air back into chamber of
the pneumatic time relay is the:
85
a. diaphragm
b. needle valve
c. shading coil
d. all of the above
564. If the motor runs but fails to stop, the problem may be:
a. open fuse
b. welded holding circuit interlock
c. jogging or plugging duty overload
d. none of the above
565. If the motor runs at half speed or “sits and hums”, look for
________ in the magnetic controller: a. an open phase
b. welded holding circuit interlock
c. both (a)and (b)
d. none of the above
566. Repeated starting and stopping is referred to as:
a. stepping
c. phasing
b. jogging
d. long acceleration time
567. A chattering or humming in magnetic contactor may be due to:
a. broken shading coil
c. both (a) and (b)
b. dirty/worn contacts
d. none of the above
568. Which of the following contacts should not be piled?
a. cadmium-plated
c. both (a) and (b)
b. silver-plated
d. none of the above
569. The minimum ampere capacity panel box used today is:
a. 30
c. 100
b. 60
d. 150
570. Number 8 wire is generally used for _______ amps:
a. 15
c. 30
b. 20
d. 40
571. Another name for emt is:
86
a. nonmetallic cable
b. flexible metallic cable
c. conduit
d. armored clad cable
572. Another name for flexible steel cable is:
a. conduit
c. synthetic cable
b. emt
d. nonmetallic
573. The common neutral wire is usually ______ in color and
connected to a:
a. black; cold water pipe
b. white; circuit breaker or fuse
c. black; circuit breaker or fuse
d. white; cold water pipe
574. A 4-way switch controls a lamp from _____ different locations:
a. 1
c. 3
b. 2
d. 4
575. The power factor rating of an inductive reactive circuit can be
increased by adding:
a. capacitors
c. coils
b. inductors
d. fuses
576. The device used to pull wire through conduit is called:
a. wire tongs
c. connectors
b. straps
d. fish tape
577. The best way to check insulation resistance is with a:
a. voltmeter
c. ammeter
b. ohmmeter
d. megohmeter
578. To decrease signal strength in strong signal areas use a:
a. splitter
c. coupler
b. amplifier
d. attenuator
579. Which of the following lamps uses a starting switch?
a. preheat
c. instant heat
87
b. rapid heat
d. all of the above
580. Which of the following lamps requires a cooling period prior to
restarting?
a. incandescent
c. mercury vapor
b. fluorescent
d. none of the above
581. The device used to attenuate specific signals is the:
a. drop tap
c. splitter
b. line tapoff
d. trap
582. The wire that is shielded is:
a. flat twinlead
b. foam-filled twinlead
c. coaxial
d. all of the above
583. Which of the following wires has 75-ohm impedance:
a. flat twinlead
c. coaxial
b. foam-filled twinlead
d. none of the above
584. The maximum capacity for a general 20A general-purpose
appliance circuit is approximately:
a. 1500 watts
c. 2400 watts
b. 1800 watts
d. 2800 watts
585. The type of thermostat most commonly used in appliance with
heating elements is the:
a. magnetic relay
c. bimetallic
b. circuit breaker
d. all of the above
586. Most heating appliances use a cord made of:
a. rubber
c. both (a) and (b)
b. asbestos cover
d. all of the above
587. Insulators are commonly made of:
a. ceramic
c. porcelain
88
b. mica
d. all of the above
588. Most cordless electric slicing knives use a charge unit and:
a. rectifier
c. diode
b. battery pack
d. none of the above
589. Heating elements can be repaired by a ______ tube which
crimps the two broken elements together:
a. nickel/silver
c. wire
b. aluminum
d. aluminum/nickel
590. Most heating elements can be checked by using a/an:
a. ammeter
c. ohmmeter
b. wattmeter
d. growler
591. One of the most common problems of a hair blower/styler is
defective:
a. cord
c. thermostat
b. transistor d. SCR
592. An overheated cord often indicates:
a. corroded terminals
c. both (a) and (b)
b. defective cord
d. none of the above
593. The insulation used in most water heater is:
a. fiberglass
c. both (a) and (b)
b. rock wool
d. none of the above
594. When examining a dead set, which item(s) should be checked?
a. power supply diodes
c. open filament
b. fuse
d. all of the above
595. The decibel reading for proper separation between channels of
multiplex unit is:
a. 50 dB
c. 20 dB
b. 10 dB
d. 40 dB
596. If only none of the transistors is a push-pull, amplifier is bad:
a. replace only the bad one
c. (a) or (b)
89
b. replace both of them
d. none of the above
597. When using an ohmmeter to identify a short, the ohmmeter
reading should indicate:
a. zero
c. 100 kilo ohms
b. infinite
d. 1 mega ohms
598. Is used to change the sequence in which the units may be
placed in and out of service in multiple unit equipment: a.
reversing switch c. accelerating switch
b. starting switch
d. unit sequence switch
599. To join two rigid steel conduits use:
a. tape
c. clamp
b. coupling
d. locknut
600. The power factor of an induction motor is:
a. leading
c. lagging
b. unity
d. zero
601. A lamp maybe controlled from three different points by:
a. 2-way
c. 3-way
b. 4-way
d. selector
602. Electromotive force is measured by:
a. ammeter
c. ohmmeter
b. voltmeter
d. wattmeter
603. This refers to the circuit conductor between the series
equipment and the branch circuit over current device: a.
service drop c. service entrance
b. feeder
d. secondary
604. One advantage of the aluminum over copper wire is:
a. higher ampacity
c. available commercially
b. higher resistance
d. cheaper
90
605. This device converts as to dc:
a. inverter
c. compensator
b. rectifier
d. transformer
606. The unit by which electric energy is sold is the:
a. kW-hr
c. ampere-hr
b. W-hr
d. lumens
607. Ohm is the unit of:
a. capacitance
b. reluctance
c. power
d. resistance
608. Burrs on sharp edges in the inside of a rigid steel conduit end
are removed with the use of:
a. reamer
c. knife
b. wrench
d. plier
609. It is a lubricant that is used to make pulling wires/cables
through conduit easier:
a. resin
c. talc
b. iron filing
d. grease
610. One horsepower is approximately:
a. 2000 watts
c. 750 watts
b. 1500 watts
d. 850 watts
611. It is a device that is used to interrupt fault current without
injury to itself:
a. fuse
c. cut-out
b. circuit breaker
d. regulator
612. It is used for direct measurement of electrical insulation:
a. megger
c. micrometer
b. volt ammeter
d. growler
613. 30A is one of the five special branch circuits rating with a circuit
conductor of:
a. 2 mm2
c. 5.5 mm2
b. 3.5 mm2
d. 8 mm2
91
614. The unit of an electrical system which is intended to carry but
not utilize electrical energy is:
a. device
c. serving drop
b. branch circuit
d. service equipment
615. The main contacts of circuit breaker are most likely to be
operated by a:
a. vacuum
c. mimic rays
b. solenoid
d. heavy duty switch
616. In
a.
b.
c.
d.
switch gear application, the term “dead front” means that:
the front and rear panels are hinged
an access door is at the end of the structure
no equipment is mounted on the front panel
energized parts are not exposed on the front panel
617. The current that a breaker must be able to carry immediately
after a fault occurs is known as:
a. interrupting current
c. exciting current
b. short-circuit current
d. momentary current
618. There is no zero sequence component of the fault current for:
a. symmetrical fault
b. single line to ground fault
c. line to line ground fault
d. double line to ground fault
619. When the primary and secondary windings take the form of a
common ring which is encircled by two or more rings of
magnetic material distributed around its periphery, the
transformer is termed as: a. grounding transformer
b. regulating transformer
c. core type transformer
d. shell type transformer
92
620. When alternating current is passing through a conductor here
is a tendency for the current to crows near the surface of the
conductor. This is known as:
a. corona
c. resistivity
b. skin effect
d. magnetization
621. Ratio of lumens reaching the work plane divided by the total
lumens generated by the lights: a. coefficient of utilization
b. illumination factor
c. maintenance factor
d. room ratio
622. The inner strand of ACSR cable is made of:
a. copper
c. lead
b. brass
d. steel
623. It is used to join a length of conduit with another:
a. tape
c. bushing
b. coupling
d. clamp
624. Pin insulators are made of:
a. paper
c. mica
b. porcelain
d. copper
625. A complete path over which an electric current can flow is:
a. load
c. circuit
b. transmission line
d. resistance
626. The power factor of an induction motor is:
a. leading
c. zero
b. 100%
d. lagging
627. Branch circuit conductors applying a single motor shall have an
ampacity of not less than ______ percent of full load current
rating:
a. 125
c. 150
b. 115
d. 200
628. In house wiring, grounded conductors must not be:
93
a. fused
b. insulated
c. placed in conduit
d. mechanically protected
629. Which of the following materials is the best conductor of
electricity?
a. nichrome
c. tungsten
b. aluminum
d. copper
630. What test is commonly made on cables after insulation:
a. insulation
c. conductance
b. resistance
d. impedance
631. What is the maximum number of quarter bends (90 degrees)
allowed in rigid metal conduit wiring between boxes?
a. no limit
c. 3
b. 2
d. 4
632. It is a point in the wiring system at which current is taken to
supply utilization equipment:
a. junction box
c. feeder
b. pull box
d. outlet
633. To protect a circuit from circuit conditions, ________ is used:
a. recloser
c. disconnect switch
b. fuse
d. alarm
634. What will happen if a 230 volt airconditioner is connected to a
115 volt line?
a. current will be less than normal
b. it runs slower
c. it will burn out
d. it will overspeed
635. Ampacity of No. 14AWG TW, three wire copper conductor cable
at 30° ambient is:
a. 15 amperes
c. 25 amperes
94
b. 20 amperes
636. Split knobs are made of:
a. wood
b. brass
d. 30 amperes
c. copper
d. porcelain
637. A device with a blank cover in a run of raceway to facilitate
pulling in of conductors is the:
a. coupling
c. outlet box
b. elbow
d. bushing
638. In an AC circuit, current equals:
a. E/R
c. E2
b. IR
d. E/Z
639. AC voltages may be increased or decreased by means of /an:
a. induction motor
c. rheostat
b. transformer
d. rectifier
640. An ammeter is connected:
a. across
b. in conjunction
c. series
d. series or parallel
641. To determine the positive wire in a single phase ac circuit:
a. use a neon lamp tester
b. use an ammeter
c. use a phase sequence meter
d. is impossible
642. Which of the following is the smallest size wire?
a. No. 20
c. No. 2
b. No. 10
d. No. 00
643. In open wire installation, the wires are supported on:
a. post insulators
c. strain insulators
b. tubes
d. knobs
644. Which of the following can reduce starting current of a large ac
motor?
95
a. magnetic starter
b. capacitor
c. compensator
d. rectifier
645. No wire smaller than number _______ is allowed for general
interior wiring:
a. 12
c. 16
b. 14
d. 18
646. The power factor of a circuit is approximately 100% if the
circuit load consists only of:
a. reactance coils
c. motors
b. capacitors
d. incandescent lamps
647. A mill is equal to:
a. 0.001 of an inch
b. one inch
c. 0.745 of an inch
d. none of the above
648. The filament of incandescent lamps is made of:
a. copper
c. aluminum
b. silver
d. tungsten
649. Operating stick for disconnect switches is made of:
a. Steel
c. wood
b. aluminum
d. brass
650. The common dry cell gives a voltage of about:
a. 1 volt
c. 1.5 volts
b. 10 volts
d. 3 volts
651. A transformer or generator inserted in a circuit to correct the
voltage is called:
a. rheostat
c. ohmmeter
b. current transformer
d. potential transformer
652. It may be used to identify blown out fuses in a live circuit:
a. ammeter
c. ohmmeter
96
b. voltmeter
d. test lamp
653. The relationship between voltage, current and resistance in a
dc circuit is called:
a. Boyle‟s law
c. Kirchhoff‟s law
b. Kelvin‟s law
d. Ohm’s law
654. It is used for transformer cores:
a. cast iron
c. brass
b. steel
d. aluminum
655. Which appliance has the largest consumption of electricity?
a. radio
c. air conditioner
b. television
d. toaster
656. A megger us used to measure:
a. insulation resistance
c. conductance
b. inductance
d. capacitance
657. It is used to measure the diameter of wires:
a. micrometer
c. caliper
b. spring balance
d. wire gauge
658. What kind of motor can be reversed by interchanging any two
leads?
a. split phase
c. series
b. shunt
d. three phase
659. What are used on the outside of the box whenever the
conduit enters an outlet box
a. bushing
c. couplings
b. locknuts
d. elbows
660. It is used to correct the power factor of fluorescent lamp?
a. rectifier
c. starter
b. varmeter
d. capacitor
97
661. It refers to the circuit conductors between the service
equipment and the branch circuit over current device: a.
service drop c. service entrance
b. feeder
d. secondary
662. It is an enclosure for surface or flush mounting with a frame in
which swinging doors are hung:
a. raceway
c. cabinet
b. switchboard
d. outlet
663. Comparing No. 12 and No. 18 bare copper wires of equal
length, the No. 12 wire will have lower:
a. weight
c. iron
b. resistance
d. carbon
664. If a fuse of higher than required current rating is employed in
a circuit, it will:
a. blow more frequently since it carried more current
b. afford better protection to the circuit
c. seriously overload the circuit
d. lead t larger maintenance
665. For flexible cable, most suitable insulation is:
a. magnesium oxide
c. insulation tape
b. glass fiber
d. polyvinyl chloride
666. Out of the following, select the best conductor of electricity:
a. graphite
c. porcelain
b. china clay
d. none of these
667. The specific resistance p is defined as:
a. resistance of a conductor which has a length of 1m and
cross-section 1m2 at 25°C
b. resistance of any conductor at 25°C
c. resistance of any conductor at 20°C
d. resistance of a conductor which has a length of 1m and a
cross-section of 1cm2 at 25°C
98
668. The value of joules mechanical equivalent of heat J, is equal
to:
a. 4.2 calories per joule
b. 4.2 calories per calorie
c. 2.4 joules per calorie
d. 4.2 joules
669. Which of the following material has nearly zero temperature
coefficient of resistance?
a. carbon
c. copper
b. porcelain
d. manganin
670. A buffer battery is used for:
a. the same purpose as floating battery
b. interconnecting dc generator and standby battery
c. trickle charge
d. decreasing variations of the voltage and the current supplied
by dc generator
671. The scale of an indicating instrument whose each division
represents the same value is known as ______ scale:
a. digital
c. numbered
b. square law
d. linear
672. Rotating field instrument is a/an ______ instrument:
a. thermal
c. electrodynamic
b. bimetallic
d. induction
673. For maximum power transfer according to maximum power
theorem source impedance:
a. must be very much larger as compared to the load
impedance
b. must be complex conjugate of lad impedance
c. must be very small as compared to the load impedance
d. must be equal to load impedance
674. An instrument which is used for measuring temperature
variations by change in metallic resistance is called a:
a. thermopile
c. bolometer
99
b. thermocouple
d. thermo-galvanometer
675. The instrument which is used for determining the magnetic
characteristics of ferr0-magnetic substances is called a:
a. flux meter
c. permeameter
b. magnetometer
d. hysteresis meter
676. Ondograph is an instrument which is used for recording:
a. wave shape of voltage or current
b. instantaneous value of voltage or current
c. over voltages with the help of brush discharge
d. synchronism of two ac voltages or voltage systems
677. In the list below, which is not a type of present day nuclear
power plant?
a. boiling water reactor
b. low pressure reactor
c. fusion fission reactor
d. fast breeder reactor
678. A device which measures speed while flashing at a pre-set
frequency is called a:
a. stroboscope
c. electroscope
b. oscilloscope
d. synchronoscope
679. Nuclear fission is similar to fusion in the sense that it also:
a. involves neutrons
b. is initiated by protons
c. needs high temperature
d. results in release of large amount of energy
680. Piezo electricity principle is applied in one of the following:
a. ultrasound equipment c. microphones
b. thermometer
d. TV sets
681. The condition in Ohm‟s law is that:
100
a. ration V/l should be constant
b. current should be proportional to voltage
c. the temperature should remain constant
d. the temperature should vary
682. When current flows in a conductor, heat is produced because:
a. heat a l2
c. of interatomic collision
b. of electronic collision
d. of Joule‟s law
683. Ohm‟s law is applicable to:
a. electric arc
b. rectifying devices
c. gas discharge lamps
d. none of these
684. Ohm‟s law can be applied with certain reservation to:
a. rectifiying devices
c. electrolytes
b. semiconductors
d. thermionic valves
685. Resistors commonly used in power circuits are:
a. carbon resistor
c. wire wound resistors
b. etched circuit resistors
d. deposited metal resistors
686. The combined resistance of two equal resistors connected in
parallel is equal to ______ to the resistance of one resistor:
a. one half
c. four times
b. twice
d. one fourth
687. The voltage drop per ampere-meter of an aluminum conductor
is higher as compared to a copper conductor of the same size
due to its higher:
a. insulation resistance
c. conductivity
b. resistivity
d. current density
688. A natural magnet is called:
a. steel
c. magnetism
b. lodestone
d. soft iron
689. Externally, magnetic line of force travel:
a. south to north
c. north to south
b. negatie to positive
d. in both directions
101
690. A material commonly
magnetism is:
a. brass
b. aluminum
used
for
shielding
or
screening
c. copper
d. soft iron
691. Bakelite is classified as:
a. flammable
c. combustion resistant
b. incombustible
d. semiconductor
692. In most electric irons, the thermostat used for controlling
temperature is:
a. vapor-filled tub
c. high-expansion steel rod
b. bimetallic strip
d. thermopile
693. If a 220V heater is used on 110V supply, heat produced by it
will be as ______ much:
a. one half
c. one fourth
b. twice
d. four times
694. The current carrying capacity of a Cu wire having the twice the
diameter of another Cu wire as _____ as great:
a. twice
c. half
b. four times
d. three times
695. For a given line voltage, four heating coils will produced
maximum heat when connected: a. all in parallel
b. all in series
c. with two parallel pairs in series
d. one pair in parallel with the other two in series
696. The electric energy required to raise the temperature of a given
amount of water is 1000 kWh. If the heat losses are 25%, the
total heating energy required is kWh.
a. 1500
c. 1333
b. 1250
d. 1000
697. Nichrome is commonly used for:
a. lamp filaments
c. heater coils
102
b. transformer
d. battery connections
698. Iron becomes magnetized by induction when it is:
a. heated
b. near to one end of a magnet
c. suspended east and west
d. treated with some chemicals
699. Maxwell‟s loop current method of solving electrical networks:
a. uses branch currents
b. utilizes Kirchhoff‟s voltage law
c. is confined to single-op circuits
d. is a network reduction method
700. Testing a blown cartridge fuse by connecting a test lamp from
one slip to the other of the suspected fuse will always indicate
a:
a. blown fuse if lamp remains dark
b. blown fuse if lamp lights up
c. good fuse if lamp lights up
d. good fuse if lamp remains dark
701. For testing insulation between the heating element and the
body of an electric iron, you would preferably use:
a. ohmmeter
c. megger
b. lamp and battery tester
d. capacitor bridge
702. Kirchhoff‟s voltage law (KVL) is connected with:
a. IR drops
c. junction voltages
b. battery efms
d. both (a) and (b)
703. Superposition theorem can be applied only to circuits having
_______ elements:
a. non-linear
c. linear
b. passive
d. resistive
704. Permeance is analogous to:
a. conductance
b. resistance
c. reluctance
d. none of these
103
705. When the magnetic flux (Ø) and the area (A) under its influence
are known, the magnetic flux density (B) can be given as:
a. B = Ø X A
c. B = A / Ø
b. B = Ø / A
d. B = Ø x A2
706. The relative permeability of paramagnetic substance is:
a. slightly less than 1
b. equal to 1
c. slightly greater than 1
d. very much greater than 1
707. The magnetization in any magnetic material appears as a result
of:
a. electrons orbital motion
b. electron spin
c. spin of the nucleus about its axis
d. all of these
708. Which of the following materials does not have permanent
magnetic dipole:
a. Paramagnetic
c. diamagnetic
b. anti-ferromagnetic
d. ferromagnetic
709. Interaction between the neighboring dipoles is negligible in
case of:
a. paramagnetic material
b. diamagnetic material
c. anti-ferromagnetic material
d. ferromagnetic material
710. Each Ferromagnetic material has characteristic temperature
above which its properties are quite different from those below
the temperature. This temperature is called: a. Transition
temperature
b. Faraday‟s temperature
c. Demagnetization temperature
d. Curie temperature
104
711. The relative permeability u for iron is:
a. 5000
c. 3000
b. 7000
d. 1000
712. Which of the following material is used for making permanent
magnets:
a. Carbon steel
b. Platinum cobalt
c. Alnico V
d. All three mentioned above
713. Which of the following statement is correct?
a. Whenever the flux linking with the coil or circuit changes
emf is produced
b. The direction of dynamically induced emf can be determined
by Flemings right hand rule
c. Coefficient of coupling for tightly coupled coil is zero
d. The coefficient of self-inductance is proportional to the
square of number of turns on it
714. Ferromagnetic materials generally behave as a:
a. semi-conductor
c. insulator
b. conduction
d. any a,b or c
715. Eddy current loss can be minimized by:
a. decreasing the resistance of magnetic medium
b. increasing the resistance of magnetic medium
c. decreasing the permeability of magnetic medium
d. none of these
716. A collapsing field around a coil:
a. tends to oppose the decay of coil current
b. helps the decay of coil current
c. tends to aid current flow reversal
d. does not effect the coil current flow
717. Which of the following is a vector quantity?
a. magnetic potential
c. magnetic field intensity
b. flux density
d. relative permeability
105
718. Whenever a conductor cuts magnetic flux, an emf is induced in
that conductor. Above statement is due to:
a. Joule‟s law
c. Faraday’s law
b. Coulomb‟s law
d. Weber and Ewings theory
719. In
a.
b.
c.
d.
the left hand, thumb always represents:
voltage
current
direction of force on conductor
magnetic field
720. While comparing magnetic and electric circuits, the flux of
magnetic circuit is compared with which parameter of electric
circuit?
a. emf
c. conductivity
b. current density
d. current
721. The law that induces emf and current always opposes the cause
producing them was discovered by:
a. Lenz
c. Maxwell
b. Farady
d. Ohm
722. The location of lightning arrester is:
a. near the transformer
b. near the circuit
c. away from the transformer
d. none of the above
723. Iron core material of inductors used in radio at high
frequencies:
a. is laminated
b. has low permeability
c. reduces inductances as well as losses
d. is called ferrite
106
724. Air-gap in the iron core of an inductor prevents:
a. core saturation
c. flux leakage
b. hysteresis loss
d. transformer
725. The time constant of an inductive circuit is defined as the ratio
of:
a. R / L
c. Lt / R
b. Rt / L
d. L / R
726. The coupling coefficient denotes:
a. the degree of magnetic linkage
b. whether the reluctance remains constant
c. the variation of inductance between the two coils
d. whether the flux linkage is constant
727. It is difficult to magnetize steel because of its:
a. low permeability
c. high permeability
b. high retentivity
d. high density
728. Hysteresis losses can be reduced by:
a. using grain-oriented silicon steel
b. increasing the frequency of the field
c. laminating the core
d. none of these
729. The purpose of shielding a meter with soft iron is to:
a. prevent damage rough use
b. keep moisture out of movement
c. protect meter movement from stray magnetic fields
d. achieve all of the above
730. A solid piece of iron:
a. is less desirable than a laminated core
b. is an excellent core material for low frequencies
c. reduces losses in an inductor
d. is the only suitable core for radio frequencies
731. The hysteresis loss can be minimized by selecting a magnetic
material having:
107
a.
b.
c.
d.
large B /H loop area
high resistivity
high retentivity
low hysteresis coefficient
732. The hysteresis loss in a given specimen of a magnetic material
may be decreased by:
a. increasing flux density through it
b. increasing frequency of reversal of magnetization
c. laminating it
d. decreasing maximum flux density established through it
733. In electrical machines, laminated cores used with view to
reducing:
a. hysteresis loss
c. friction loss
b. eddy current loss
d. copper loss
734. The process by which metallic parts are demagnetized is called:
a. demagnetizing
c. degrading
b. degaussing
d. degreasing
735. The absolute permitivity of vacuum is taken as:
a. 8.854 x 10-6 farad/m c. 8.854 x 10-9 farad/m
b. 8.854 x 10-12 farad/m d. none of the above
736. The unit of field intensity is:
a. coulomb
b. coulomb/m2
c. newtons/coulomb
d. None of the above
737. If a test lamp lights up when connected in series with a
capacitor and a suitable dc supply, it clearly shows that the
capacitor is:
a. short-circuited
c. fully-discharged
b. fully-charged
d. open-circuit
108
738. The electrical equipment occasionally connected across relay
contacts for minimizing arcing is a/an:
a. resistor
c. carbon tip
b. inductor
d. capacitor
739. A charge of 100 coulombs are transferred I a circuit by a
current of 1A. Time taken by this current is ______ seconds:
a. 1
c. 100
b. 10
d. 1000
740. One of the best ways to check for an open electrolytic capacitor
in a circuit is to:
a. temporarily connect a known good capacitor across it
b. remove it and insert a good one
c. measure d voltage across it
d. use capacitor checker
741. Which one of the following types of capacitor is polarized?
a. electrolytic
c. paper
b. ceramic
d. mylar
742. Present day capacitors which have high capacitance in small
size use a dielectric of:
a. paper
c. ceramic
b. rubber
d. mylar
743. Dielectric strength of a material depends on:
a. moisture content
c. temperature
b. thickness
d. all of the above
744. Which medium has highest value of dielectric strength?
a. glass
c. porcelain
b. mica
d. quartz
745. Capacitors are said to
a. block ac and pass dc
b. block dc and pass ac
c. pass ac and dc
d. block ac and dc
746. The effect of the dielectric is to
a. increase the capacitance
109
b. decrease the capacitance
c. reduce the working voltage
d. increase the distance between the plates
747. One farad is
a. coulomb-Joule
c. Joule per volt
b. one coulomb per volt d. one volt per coulomb
748. The power dissipated in a pure capacitor is
a. maximum
b. minimum
c. zero
d. depends on the size and voltage
749. In
a.
b.
c.
d.
a capacitor, the electric charge is stored in
metal plates
dielectric
dielectric as well as metal plates
none of the above
750. If a dielectric is placed in an electric field, the field strength
a. decreases
c. remain the same
b. increases
d. becomes zero
751. A capacitance C is charged through a resistance R. The time
constant of the charging circuit is given by
a. RC
c. C/R
b. 1/(RC)
d. R/C
752. A circuit component that opposes the changes in the circuit
voltage is
a. resistance
c. capacitance
b. inductance
d. none of the above
753. The mass of an ion liberated at an electrode is directly
proportional to the quantity which passes through the
electrolyte. The above statement is associated with
110
a. Gauss‟ theorem
b. Laplace law
c. Weber and Ewing‟s theory
d. Law of electrolysis
754. In electroplating, the positive electrode is called the
a. cathode
c. anode
b. terminal
d. iontrap
755. One factor affecting voltages of the primary cells is the
a. area of the plates
b. distance between the plates
c. types of plates and electrolytes
d. thickness of the plates
756. The condition of a liquid electrolyte is measured in terms of
its
a. current value
c. acid content
b. specific gravity
d. voltage output
757. The action in the primary cell can be rectified by
a. chemical action to mechanical energy
b. chemical action to electrical energy
c. electrical energy to mechanical energy
d. electrical energy to magnetic energy
758. The two main effects of the primary cell are
a. polarization and sulfation
b. local action and polarization
c. bucking and polarization
d. sulfation and bucking
759. Cells are connected in parallel to
a. increase the internal resistance
b. decrease the current capacity
c. increase the current capacity
d. increase the voltage output
760. The composition of secondary cell is
a. zinc, copper and dilute sulfuric acid
b. zinc, carbon and dilute sulfuric acid
111
c. lead, lead peroxide and dilute sulfuric acid
d. none of the above
761. The condition of a secondary cell can be determined by
a. its terminal voltage
b. the color of the electrolyte
c. level of the electrolyte
d. the terminal voltage and strength of the electrolyte
762. Electrolyte of a storage battery is formed by adding
a. water to hydrochloric acid
c. hydrochloric acid to water
b. sulfuric acid to water
d. water to sulfuric acid
763. Lead is the metal which is commonly used for
a. transformer core
c. electromagnets
b. storage batteries
d. knife-switch blades
112
764. When liquid level in a lead-acid cell is low, the proper remedy
is to
a. add only distilled water
b. add weak acid solution
c. empty out the cell and replace the entire solution
d. do nothing till plates becomes fully exposed
765. The active materials on the positive and negative plates of a
fully-charged lead-acid cell are
a. lead peroxide and pure lead
b. pure lead and lead sulfate
c. lead peroxide and lead sulfate
d. pure lead and pure lead
766. A lead acid battery should not be left in discharged state for
long otherwise
a. acid will evaporate
b. plates will become sulfated
c. electrolyte will start attacking the plates
d. terminals will get corroded
767. When making new electrolyte by mixing sulfuric acid and
water, acid should be poured into water to avoid a. corrosion
of mixing vessel
b. use of too much acid
c. making initial mixture too weal
d. generation of excess heat
768. A battery:
a. always absorbs water
b. always delivers power
c. can absorb or deliver power depending upon the circuit to
which it is connected
d. absorbs power when the internal resistance is non-zero but
delivers power when the internal resistance is zero
a.
b.
c.
d.
113
769. Which of the following gives best indication of a fully-charged
battery?
open-circuit cell voltage
level of electrolyte specific
gravity temperature of the
electrolyte 770. A battery is
said to be „floating‟ on the
battery-bus when
a. its supplied at the load
b. its voltage is higher than the bus voltage
c. charger is shut down
d. battery voltage equals the charger voltage
771. The storage battery most commonly used in industry today is
_______ battery:
a. silver-zinc
c. zinc cadmium
b. lead acid
d. nickel cadmium
772. Distilled water is variably used in electrolytes because it:
a. prevents polarization
b. prevents local action
c. accelerates electrochemical action
d. improves specific gravity of the electrolyte
773. The action of all batteries is dependent on:
a. dilute sulfuric acid
c. electrochemical action
b. electrolysis
d. lead peroxide
774. High battery voltages can be obtained by:
a. connecting cells in series
b. connecting cells in parallel
c. using large size cells
d. increasing quantity of electrolyte
a.
b.
c.
d.
114
775. The specific gravity of a lead-acid cells is often used as a
measure of its:
a. rate of discharge
c. state of charge
b. operating temperature
d. life expectancy
776. The sole purpose of using separators in a storage battery is to
prevent the plates from:
a. touching the container
c. shorting together
b. touching the electrolyte
d. shorting to the bottom
777. The most important advantage of nickel-cadmium battery over
a nickel-iron battery is its:
higher voltage
greater strength ability
to hold a charge all of
the above
778. The most common impurity found in the battery electrolyte is:
a. sodium chloride
c. lead
b. iron
d. dust
779. Excessive overcharging of a lead-acid battery will cause:
a. increased internal resistance
b. excessive gassing
c. loss of water
d. all of the above
780. Main difference between primary and secondary cells is that
secondary cells:
a. give higher voltage
c. store electric charge
b. absorb hydrogen
d. can be charged
781. The ampere hour capacity of battery depends on:
a. the thickness of the plates
b. the area of the plates
c. the strength of the electrolytes
a.
b.
c.
d.
115
d. the distance between the plates
782. The internal resistance of a discharged battery:
a. is more
c. remains constant
b. is less
d. is negative
783. A partially discharged lead storage lead storage battery may
be brought back to full charge by: a. adding sulfuric acid
b. adding distilled water
c. applying ac voltage across the terminal
d. applying dc voltage across the terminal
784. Charging a lead-acid cell causes the electrolyte to become :
a. stronger
c. weaker
b. stable
d. water
785. A cell which is used as voltage reference source for instrument
calibration is:
solar cell
dry cell
mercury-cadmium cell nickel-cadmium
cell
a.
b.
c.
d.
116
786. A fuel cell converts _______ energy into electrical energy:
a. mechanical
c. chemical
b. magnetic
d. solar
787. The output voltage of a single loop generator is a:
a. steady dc
c. pulsating dc
b. steady ac
d. pulsating ac
788. What effect on current flow does reversing the direction of
movement of a conductor in the magnetic field of a generator
have :
a. neutralizes the current flow
b. has no effect on current
c. it reverses the direction of current flow
d. none of the above
789. In
a.
b.
c.
d.
most generators the output voltage is induced by:
rotating magnetic field past stationary coils
relative motion between the field and the armature coils
converting electrical energy into mechanical energy
none of the above
790. What classification is given to a dc generator that receives its
field excitation current from internal source?
a. self-excited
c. separately-excited
b. controlled excite
d. internally excited
791. The shunt filed of a compound generator is connected across
both series field and the armature. This connection is known
as:
a. short shunt
c. differential compound
b. long shunt
d. cumulative compound
792. In a DC generator, the flux is seen to be _____ at the trailing
pole tips and also ______ at the leading pole tips:
a. weakened, weakened c. crowded, weakened
b. weakened, crowded
d. same, same
117
793. Electric dc generators have normally, an overall efficiency of
the order of:
a. 60-80%
c. 80-90%
b. 75-85%
d. 85-95%
794. Residual magnetism is necessary in a:
a. separately excited generator
b. self excited generator
c. both of these
d. none of these
795. The armature magnetic field has effect that:
a. it demagnetizes or weakens the main flux
b. it cross magnetizes, or distorts it
c. it magnetizes or strengthens the main flux
d. (a) and (b)
796. In
a.
b.
c.
d.
the commutation process it is the:
current which is getting reversed
voltage which is getting reversed
both of these
none of these
797. In any DC generator, the emf generated in the armature is
maximum when:
a. rate of change of flux linked is minimum
b. rate of change of flux is maximum
c. flux linked with conductor is maximum
d. flux linked with conductor is minimum
798. A simple method of increasing the voltage of a DC generator
is:
a. to decrease the air gap flux density
b. to increase the speed if rotation
c. to decrease the speed of rotation
d. to increase the length of the armature
799. The function of interpole or compole is:
118
a. to neutralize the reactance voltage and help in commutation
process
b. to neutralize the cross-magnetizing effect of armature
reaction
c. to neutralize the demagnetizing effect of the armature
d. (a) and (b)
800. Critical resistance of a DC generator Rc
a. Rc α (speed)-1
c. Rc α (speed)2
b. Rc α (speed)
d. Rc α (speed)-2
801. Interpoles are connected in _____ with the armature and
compensating windings are connected in _______ with the
armature:
a. series, series
c. shunt, series
b. series, shunt
d. shunt, shunt
802. Generators are often preferred to be run in parallel because of
having the advantages of: a. great reliability
b. generator efficiency
c. meeting greater load demands
d. all of the above
803. Shunt generator are used where the main requirement is a
constant:
a. current and voltage
b. current
c. voltage over a wide load range
d. voltage over a narrow load range
804. Equalizer connections are required when paralleling two:
a. compound generators c. shunt generators
b. series generators
d. none of the above
805. Interpoles are normally connected in:
a. parallel with the field c. parallel with the field
b. series with the field
d. series with the load
119
806. DC generator preferred for charging automobile batteries is:
a. shunt generator
b. series generator
c. long shunt compound generator
d. none of the above
807. Which loss in DC generator varies with the load
a. copper loss
c. hysteresis loss
b. eddy current loss
d. windage loss
808. The armature of a DC generator is laminated to:
a. reduce the bulk
b. insulate the core
c. reduce eddy current loss
d. provide passage for cooling air
809. In a shunt generator, the voltage built up generally restricted
by:
a. speed limitation
c. saturation of iron
b. armature heating
d. none of the above
810. With DC generator, which of the following regulation is
preferred:
a. 1% regulation
c. infinite regulation
b. 50% regulation
d. 100% regulation
811. The function of the commutator in a DC generator is:
a. to change alternating current into direct current
b. to improve commutation
c. for easy speed control
d. to change alternating voltage into direct voltage
812. Carbon brushes are used in electric motors to:
a. brush off carbon deposits on the commutator
b. provide a path for flow of current
c. prevent overheating of armature windings
d. prevent sparking during commutation
120
813. The speed of a DC motor is:
a. directly proportional to back emf and inversely proportional
to flux
b. inversely proportional to back emf and directly proportional
to flux
c. directly proportional to emf as well as flux
d. inversely proportional to emf as well as flux
814. An external resistance is added in the series with the field of a
DC shunt motor. When the motor runs, the effect of resistance:
a. to reduce the speed of the motor
b. to increase the speed of the motor
c. to reduce the armature current drawn by the motor
d. to reduce the losses
815. If the speed of the DC shunt motor increases, the back emf:
a. increases
b. decreases
c. remain constant
d. decreases and then increases
816. In a DC motor iron losses occur in:
a. the yoke
c. the field
b. the armature
d. none of these
817. The current flowing in the conductors of a DC motor will:
a. AC
c. AC as well as DC
b. DC
d. transients
818. As the load is increased, the speed of a DC shunt motor will:
a. remain constant
c. increase slightly
b. increase proportionately
d. reduce slightly
819. One DC motor drives another DC motor. The second DC motor
when excited and driven: a. runs
b. does not run as a generator
c. runs as a generator
121
d. also runs as a motor
820. In dc shunt motors, if the terminal voltage is reduced to half
and torque remains the same, then:
a. speed will be half and armature current also will be half
b. speed will be half but armature current remains the same
c. speed will be half and armature current becomes double
d. speed and armature current will remain the same
821. The torque of a motor is:
a. the force in N-m acting on the rotor
b. the product of tangential force on the rotor and its radius
c. the electrical power in KW
d. the power given to load being driven by the motor
822. The power stated on the name plate of any motor is always:
a. the output power at the shaft
b. the power drawn in KVA
c. the power in KW
d. the gross power
823. The speed of a series motor at no load is:
a. Zero
c. 1800 rpm
b. 3000 rpm
d. infinity
824. A starter is necessary to start a DC motor because:
a. it starts the motor
b. it limits the speed of the motor
c. it limits the back emf t a safe value
d. it limits the starting current to a safe value
825. The direction of rotation of a DC motor is reversed by:
a. reversing armature connections
b. interchanging the armature and field current
c. adding resistance to field current
d. reversing supply connection
826. Which of the following is a correct statement about a series
motor?
122
a.
b.
c.
d.
its field winding consists of thicker wire and less turns
it an run easily without load
it has am almost constant speed
it has poor torque
827. If the back emf in a DC motor is absent, then:
a. motor will run at very high speed
b. motor will run at very low sped
c. motor will not run at all
d. motor will burn
828. A series motor is started without load. The effect is that:
a. the torque increases rapidly
b. the speed increases rapidly
c. the current drawn increases rapidly
d. the back emf decreases
829. If the field of a DC shunt motor is opened:
a. it will continue to run at its rated speed
b. the speed of the motor will become very high
c. the motor will stop
d. the speed of motor will decrease
830. Interpoles are meant for:
a. increasing the speed of the motor
b. decreasing counter emf
c. reducing sparking at the commutator
d. converting armature current to dc
831. Armature reaction is attributed to:
a. the effect of magnetic field set-up by the armature current
b. the effect of magnetic field set-up by field current
c. copper loss in the armature
d. the effect of magnetic field set-up by the back emf
123
832. When the electric train is moving down a hill the DC motor acts
as:
a. DC series motor
b. DC shunt motor
c. DC series generator
d. DC shunt generator
833. Which of the following motors is suitable for high starting
torque?
a. shunt motor
b. cumulative compound motor
c. series motor
d. compound motor
834. It is preferable to start a DC series motor with some mechanical
load on it because: a. it will not un at no load
b. it acts as starter to the motor
c. it may develop excessive speed and damage itself
d. none of these
835. If the flux of a DC motor approaches zero, its speed will
approach:
a. infinity
b. zero
c. a stable value nearer to the speed
d. none of these
836. As the load is increased, the speed of a shunt motor:
a. remains constant
c. reduces slightly
b. increases slightly
d. none of these
837. The main function of a commutator in DC motor is to:
a. prevent sparking
c. reduce friction
b. convert AC to DC
d. convert DC to AC
838. A 60 Hz frequency would cause an electric light to:
a. turn on and off 120 times per second
b. flicker noticeable
c. turn on and off 180 ties per second
124
d. turn on and off 60 times per second
839. The greatest value attained during one half of the cycle is called
the:
a. peak value
c. RMS value
b. average value
d. effective value
840. The RMS value of a sine wave is equal to:
a. 0.637 max value
c. 0.506 max value
b. 0.707 max value
d. 1.414 max value
841. Form factor is defined as:
a. RMS value/peak value
b. max value/ RMS value
c. RMS value/average value
d. effective value/ RMS value
842. The value form factor for pure sine wave is:
a. 1.414
c. 0.637
b. 0.707
d. 1.110
843. The value of peak factor for a pure sine wave is:
a. 1.414
c. 0.637
b. 0.707
d. 1.110
844. If the current and voltage are out of phase by 90°, the power
is:
a. 1.10 Vl
c. minimum
b. maximum
d. zero
845. RMS value and the mean value is the same in case of:
a. square wave
b. sine wave
c. triangular wave
d. half wave rectified sine wave
846. The form factor of DC supply voltage is always:
125
a. infinite
c. 0.5
b. Zero
d. unity
847. When the sole purpose of an alternating current is to product
heat, the selection of conductor is based on:
a. average value of current
c. RMS value of current
b. peak value of current d. any of the above
848. In the impedance triangle, the inductive reactance and
impedance phasor are analogous to the _______ and _____
phasor respectively in the voltage triangle: a. inductive voltage,
total voltage
b. inductive current, total current
c. inductive voltage, resistive voltage
d. inductive current, resistive current
849. The phase angle of a series RL circuit is the angle between the
______ phasor and the ______ phasor: a. resistance, inductive
reactance
b. resistance, impedance
c. inductive reactance, impedance
d. none of these
850. Fr an RL circuit, the power factor cannot be less than _____ or
greater than _______: a. 0, 1
b. 1, 0
c. 0, -1
d. –1, 0
851. If the resistance in a series RC circuit is increased the
magnitude of the phase angle: a. increases
b. remains the same
c. decreases
d. change in an indeterminate manner
852. The resistance phasor for a series RC circuit points to the right.
The capacitive reactance phasor points _______ while the
diagonal of the rectangle having there two phasors as sides
represent the _______: a. up, impedance
b. down, impedance
c. left, current
126
d. up, total voltage
853. There will ________ be a frequency, called the ______
frequency, at which _________: a. sometimes, natural; XL –
XC
b. always, natural; R = 0
c. always, resonant; XL = XC
d. sometimes, resonant; R = 0
854. In an RLC circuit, the impedance at resonance is:
a. maximum
c. infinity
b. minimum
d. zero
855. At
a.
b.
c.
d.
a frequency less than the resonant frequency:
series circuit is capacitive and parallel circuit is inductive
series circuit is inductive and parallel circuit is capacitive
both circuits are inductive
both circuits are capacitive
856. The value of current at resonance in a series RLC cicuit by the
value of:
a. R
c. L
b. C
d. all of these
857. In resonant circuits, the power-factor at resonance is:
a. zero
c. 0.50
b. 1
d. 0.707
858. Which of the following statements is true for a series RLC circuit
tuned at resonant frequency?
a. the voltage across C> applied voltage
b. the voltage across L> applied voltage
c. the voltage across L and C> the applied voltage
d. the voltage across both L and C< the applied voltage
859. The current flowing in L and C at parallel resonance are:
a. zero
c. infinite
127
b. equal
d. different
860. A coil with large distributed capacitance has a:
a. low resistance
b. low o
c. low resonant frequency
d. high resonant frequency
861. The transient current is due to:
a. voltage applied to circuit
b. resistance of the circuit
c. impedance of the circuit
d. changes in stores energy is inductive and apacitance
862. To a highly inductive circuit, a small capacitance is added in
series. The angle between voltage and current will:
a. increase
c. remain nearly the same
b. decrease
d. become indeterminate
863. In a balanced three phase star connected circuit the line
voltage are equal:
a. to the line current
b. to the phase voltage
c. and so are the line current
d. but the line currents are equal
864. The type of AC distribution system commonly used to supply
both light and power is the: a. open delta system
b. three phase delta system
c. three phase star system with neutral wire
d. three phase star system without neutral wire
865. In a balanced three phase star connected system the line
voltage is:
a. the phasor difference of the two phase voltages
b. the phasor sum of the two phase voltages
c. 0.707 times the phase voltage
d. 1.414 times the phase voltage
128
866. The advantages of star connections over delta connections for
same phase voltage is that it gives:
a. step down current
c. extra step up current
b. extra step up voltage d. extra step up power
867. Power in a three phase delta system with balanced load is equal
to:
a. √3 x VL x lL x power factor
b. √3 x VPH x lPH x power factor
c. √3 x VPH x lL x power factor
d. 3 x VL x lL x power factor
868. Power in star connected system is:
a. equal to that of delta system
b. √2 times the delta system
c. √3 times the delta system
d. 3 times of a delta system
869. What is the minimum number of wattmeters required for
measuring power of a three phase balanced load?
a. two
c. one
b. four
d. three
870. What is the minimum number of wattmeters required to
measure unbalanced power for a three phase system?
a. two
c. three
b. four
d. one
871. In a 2-wattmeter method, the reading of one of the wattmeters
will be zero when: a. power factor is unity
b. power factor is 0.50
c. load in one of the phase is zero
d. a neutral wire is not provided
872. For a three phase will be in proportional to the load:
a. the power factor of each phase will be in proportional to the
load
b. the power factor of each phase will be the same
129
c. the power factor of at least one of the phase must be leading
d. the power factor of each phase maybe different
873. In a pure reactive circuit, the power factor is:
a. lagging
c. leading
b. zero
d. unity
874. The capacitor of power factor correction are rated in terms of:
a. Voltage
c. KW
b. VA
d. KVAR
875. In an AC circuit, a low value of reactive volt ampere compared
with watts indicates:
a. high power factor
c. leading power factor
b. unity power factor
d. none of the above
876. For a parallel circuit consisting of resistance the value of power
factor is the ratio of: a. impedance to reactance
b. reactance to impedance
c. resistance to impedance
d. impedance to resistance
877. For the same load, if the power factor of load is reduced, it will
draw:
a. more current
b. less current
c. same current but less power
d. less current but more power
878. One of the reasons for improving the power factor is:
a. to increase the reactive power
b. to decrease the reactive power
c. to increase the real power
d. none of the above
879. The advantage of using static capacitor to improve the power
factor is because they: a. are not variable
b. are almost loss free
c. provide continuous change of power factor
d. none of the above
130
880. An ideal current source has zero:
a. voltage on no load
c. internal conductance
b. internal resistance
d. none of the above
881. A passive network has:
a. no source of emf
b. no source of current
c. neither source of current nor source of emf
d. none of the above
882. Which of the following statement is not correct?
a. voltage source is an active element
b. current source is a passive element
c. resistance is a passive element
d. conductance is a passive element
883. A closed path made of several branches of the network is
known as:
a. loop
c. branch
b. junction
d. none of the above
884. Which of the following is not non-linear element?
a. diode
b. transistor
c. heater coil
d. electric arc with unlike electrodes
885. For open circuited condition of Thevenin‟s theorem, all sources
of emf in the network are replaced by: a. their internal
impedance
b. their internal resistance
c. as total a big source of emf
d. none of the above
886. Open circuit voltage is the pd between two when the impedance
between these points is:
a. infinity
c. zero
131
b. reactive
d. capacitive
887. In order to find Z in Thevenin‟s theorem:
a. all independent voltage and current sources are short
circuited
b. circuited all independent voltage sources are short circuited
and all independent current sources are open
c. all independent current sources are short circuited and
independent voltage sources are open circuited
d. all independent voltage sources are open circuited and all
independent current sources are open circuited
888. Reciprocity theorem is valid for:
a. active network only
b. passive network only
c. active and passive network only
d. none of the above
889. The superposition theorem is applicable to:
a. linear responses only
b. linear and non-linear impedance
c. linear, non-linear and time variant response
d. none of the above
890. Which of the following theorems enable a number of voltage
(or current) source to be combined directly into a single voltage
(or current) source?
a. Compensation theorem
c. Superposition theorem
b. Reciprocity theorem
d. Millman’s theorem
891. In compensation theorem a network containing generator can
be replaced by:
a. its zero internal resistance
b. its infinite resistance
c. another generator
d. LC circuit
892. Norton‟s theorem reduces a two terminal network to:
a. a constant voltage source and an impedance in parallel
b. a constant voltage source and an impedance in series
c. a constant current source and an impedance in parallel
132
d. a constant current source and an impedance in series
893. For maximum power transfer, according to maximum power
transfer theorem, source impedance:
a. must be very much large as compared to the load
impedance
b. must be complex conjugate of load impedance
c. must be equal to load impedance
d. must be very small as compared to the load impedance
894. The principle of working of a transformer is:
a. static induction
c. mutual induction
b. dynamic induction
d. self induction
895. Transformer is used to change the value of:
a. frequency
c. power
b. voltage
d. power factor
896. The laminations are made from:
a. low carbon steel
b. silicon steel sheet
c. nickel alloy steel stampings
d. chrome steel sheets
897. What is common in the two windings of a transformer:
a. electric circuit
c. winding wire gauge
b. magnetic circuit
d. none of these
898. Preferably, the resistance between the primary and the
secondary of a transformer should be: a. as low as possible
b. as high as possible
c. low or high depending upon whether it is step up or sep
down
d. high or low depending upon whether it is step up or step
down
899. Ideal transformer assumptions do not include:
133
a.
b.
c.
d.
zero reactance of windings
zero resistance of windings
no leakage flux
no saturation of core
900. The reactance of a transformer is determined by its:
a. leakage flux
b. common core flux
c. size of the core
d. permeability of the material of the core
901. The resistance of low voltage side of a transformer:
a. is equal to resistance of its high voltage side
b. is more than resistance of its high voltage side
c. is less than the resistance of its high voltage side
d. (b) or (c)
902. The basic property of the transformer is that it changes the
voltage level of an AC signal:
a. without changing the power
b. without changing its shape
c. without changing its frequency
d. without changing power, frequency or shape
903. At every instant the direction of secondary current in a
transformer must be such as to oppose any change in flux. Th
is in accordance with:
a. Faraday‟s law
c. Lenz’s law
b. Joule‟s law
d. Coulomb‟s law
904. The magnitude of mutual flux in a transformer is:
a. low at low loads and high at high loads
b. high at low loads and low at high loads
c. same at all levels
d. varies at low loads and constant at high loads
905. Transformers are rated in:
a. kW
c. k-WH
b. kV
d. kVA
134
906. What type of core is used for a high frequency transformer?
a. air core
c. aluminum core
b. closed iron core
d. open iron core
907. The no-load current of a transformer in terms of full load
current is usually:
a. 1 to 3%
c. 9 to 12%
b. 3 to 9%
d. 12 to 20%
908. Which of the following is a correct statement about eddy
currents?
a. eddy currents improve the efficiency of a motor
b. eddy currents heat up the metal parts
c. eddy currents do not influence the movement
d. eddy currents are used for arc welding
909. Which of the statement given below is true about
autotransformer?
a. it has two separate windings connected in series externally
b. it can only step down the voltage
c. it has only one winding
d. it is most suitable for power transformer
910. In any transformer, the voltage per turn in primary and
secondary remains:
a. always different
c. always in ratio of K
b. always same
d. sometimes same
911. Power transformers are designed to have maximum efficiency
at:
a. no load
c. near full load
b. half load
d. little more than full load
912. As compared to an amplifier a transformer cannot:
a. increase output power
135
b. increase the output current
c. increase the output voltage
d. none of these
913. Two transformers when operating in parallel will share the load
depending upon their:
a. magnetizing current
c. per unit impedance
b. leakage reactance
d. efficiency
914. All day efficiency of a transformer ηA:
a. ηA = Electrical efficiency of transformer
b. ηA > Electrical efficiency of transformer
c. ηA < electrical efficiency of transformer
d. none of these may be true
915. No load primary output is practically equal to the iron losses in
the transformer because:
a. primary current is small
b. secondary current is small
c. both the current are small
d. no load input is not equal to iron losses
916. If the supply frequency to the transformer is increased, the iron
loss will:
a. decrease
c. no not change
b. increase
d. none of the above
917. The size of the transformer core will depend on:
a. frequency
b. flux density of the core material
c. area of the core
d. (a) and (b) both
918. Alternators mostly work on rotating field type principle which
is different from DC machines where the field is stationary.
Therefore, the alternators:
a. don‟t obey Faraday‟s law
b. work on Faraday’s law
c. do not obey Lenz‟s law
136
d.
919. In
a.
b.
don‟t obey Ohm‟s law
huge alternators, the moving part is:
brushes
c. poles
armature
d. none of these
920. High alternators have a rotor construction
a. similar to DC machines
c. of salient type
b. of non-salient type
d. none of the above
921. The voltage applied to the field of a rotating cylindrical rotor
type alternators:
a. high DC voltage
c. low DC voltage
b. high AC voltage
d. low AC voltage
922. Alternators are usually designed to generator to generate:
a. variable frequency
c. definite frequency
b. definite currents
d. definite power factor
923. The standard practice, now a days in alternators is to have:
a. rotating field
b. rotating armature
c. either rotating field or rotating armature
d. none of the above
924. When the speed of alternators increases, the frequency:
a. decreases
c. increases
b. remains same
d. changes
925. Distributing the armature winding of alternator in more than
one number of slots per pole per phase results is:
a. reduction of irregularities produced in the waveform
b. economy of materials used in winding
c. less weight of the entire armature
d. increase of generated emf per phase
926. For two alternators in parallel, if the load shared by one of them
is:
137
a.
b.
c.
d.
To be strengthened keeping input torque same
To be weakened keeping input torque same
To be kept constant but input torque should be increased
None of these
927. When the power factor of load is unity, the armature flux of an
alternator will be:
a. demagnetizing
c. cross magnetizing
b. square wave form
d. none of these
928. An alternator is said to be over-excited if it is operating at:
a. leading pf
c. unity pf
b. lagging pf
d. none of these
929. If the input of the prime mover of an alternator is kept constant
but the excitation is increased the: a. KVA will be leading
b. KVA will be lagging
c. KW will be changed
d. the power factor of the load remain constant
930. If Xs = the synchronous reactance of the machine,
Xe
= leakage reactance and Xa = reactance due to armature flux
then:
a. Xa = Xs – Xe
c. Xa = Xe – Xs
b. Xa = Xs + Xe
d. Xe = XsXa
931. High voltage alternators are usually of the rotating field type.
This means the generated voltage is connected: a.
through slip rings to the load
b. through slip rings to the rotating field
c. directly to load
d. directly to rotor
932. The maximum current that can be supplied by alternator
depends upon the:
a. strength of the exciter voltage
b. number of poles
c. strength of the magnetic fluid
d. maximum heat dissipation
138
933. Synchronous impedance of an alternator is defined as the ratio
of:
a. short circuit voltage to short circuit current
b. open circuit voltage to short circuit current
c. short circuit current to no load current
d. open circuit voltage to short circuit current for same value
of excitation
934. Pitch factor is defined as the ratio of the emf‟s of:
a. distribution winding to full pitch winding
b. short pitch coil to full pitch coil
c. full pitch winding to short pitch winding
d. full pitch winding to concentrated winding
935. Synchronization of alternators means:
a. connecting alternators in series
b. transferring load from one alternator to another
c. connecting alternators in parallel
d. adjusting the excitation of the alternator
936. For synchronizing three phase alternator, the additional
requirements is that the phase rotation:
a. must be the same
c. is anti-clockwise
b. is clockwise
d. none of the above
937. Adjustment of field excitation on one of the two alternators
operating in parallel:
a. increase its load
c. decreases its load
b. change its frequency
d. change its power factor
938. If the input to the prime mover of an alternator is kept constant
but the excitation is changed, then
a. the reactive component of the output is changed
b. the active component of the output is changed
c. the p.f. of the load remains constant
d. none of the above
939. Synchronous motor is capable of being operated at
139
a.
b.
c.
d.
lagging power factor only
leading power factor only
lagging and leading power factor
none of these
940. When the stator windings are connected in such a fashion that
the number of poles are made half, the speed of the rotor of a
synchronous motor
a. decreases to half the original value
b. remains same as the original value
c. increases to two times the original value
d. tends to become zero
941. The maximum power developed in a synchronous motor
occurs at a coupling angle of
a. 0°
c. 90°
b. 45°
d. 180°
942. Synchronizing power of a synchronous machine is:
a. equal to synchronous reactance
b. inversely proportional to the synchronous reactance
c. directly proportional to the synchronous reactance
d. none of these
943. Synchronous motors are:
a. self-starting
c. essentially self-starting
b. not self-starting
d. none of these
944. An over-excited synchronous motor take:
a. lagging current
b. leading current
c. lagging and leading current
d. none of these
945. The motor in which stator and rotor magnetic field rotate at the
same speed is:
a. induction motor
c. universal motor
b. reduction motor
d. synchronous motor
140
946. In
a.
b.
c.
d.
a synchronous motor, the torque angle is:
the angle between the rotating stator flux and rotor poles
the angle between the magnetizing current and back emf
the angel between the supply voltage and the back emf
none of the above
947. In a synchronous motor, which loss does not vary with load?
a. copper losses
c. windage losses
b. hysteresis losses
d. none of the above
948. A three phase synchronous motor is running clockwise. In case
the direction of its field current is reversed:
a. the motor will continue to run in the same direction
b. the motor will run in the reverse direction
c. the motor will stop
d. the winding of the motor will burn
949. The speed regulation of a three phase synchronous motor is:
a. 5%
c. 0.4%
b. 1%
d. zero
950. The speed of a synchronous motor:
a. reduce as load increases
b. increases as load increases
c. adjust itself to new equilibrium speed whenever load
changes
d. always remains constant
951. When a three phase synchronous generator is supplying a zero
pf lagging load the armature field effects the main field in the
following way:
a. directly opposes it
c. augment it directly
b. dross-magnetizes it
d. none of the above
952. The armature current of the synchronous motor has large
values of
a. low excitation only
b. high excitation only
141
c. both low and high excitation
d. none of the above
953. The type of the motor that does not have a commutator is the:
a. repulsion motor
c. DC shunt motor
b. induction motor
d. universal motor
954. The rotor speed of an induction motor is:
a. the same as the synchronous speed
b. faster than the synchronous speed
c. slower than the synchronous speed
d. determined by frequency and the number of poles
955. The induction motor differs from the synchronous motor is that
its:
a. requires a DC source for its rotor
b. does not require a rotating magnetic field
c. current is induced in its rotor
d. current is conducted in rotor
956. Squirrel cage induction motor differs from the slip ring type in
that it has no:
a. slip rings
c. windings on the stator
b. rotor windings
d. rotating part
957. Squirrel cage induction motor has:
a. zero starting torque
b. very small starting torque
c. very high starting torque
d. extra starting torque and it start up for rest
958. The frequency of the rotor current in an induction motor is
given by (if f is the supply frequency, f‟ is the rotor frequency
and S is the slip)
a. f = Sf‟
c. S = ff‟
b. f’ = Sf
d. none of the above
959. Improvement in the power factor in an induction motor:
a. decreases torque
142
b. increases the torque
c. increases the current
d. increases the torque and decreases the current due to
increased impedance
960. In an induction motor the torque is related with the supply
voltage as:
a. T α V½
c. T α V2
b. T α V
d. T α 1/V2
961. Torque under running condition is maximum at the slip “S”:
a. which makes rotor reactance/phase equal to rotor
resistance/phase
b. which makes rotor reactance/phase greater than rotor
resistance/phase
c. which makes rotor reactance/phase lesser than rotor
resistance/phase
d. which is independent of rotor resistance
962. Short circuit test on the induction motor can be used to find
out:
a. the transformation ratio of the induction motor
b. power scale of circle diagram
c. copper losses in the induction motor
d. all of the above
963. Which of the following is a correct relation for an induction
motor?
actualspeedof rotor
a. rotorefficiency
synchronous speed
b. rotor copper loss = slip x rotor input
c. rotor input = 2 x  x gross torque x synchronous speed
d. all of the above relations are correct
964. If the air gap of the induction motor is increased:
a. the magnetizing current will decrease
b. the magnetizing current will increase
143
c. the power factor will decrease
d. none of the above
965. It is advisable to avoid line starting of induction motor and use
starter because:
a. starting torque is very high
b. motor takes five to seven times its full load current
c. it will pick up very high speed and may go out of step
d. it will run in reverse direction
966. When using any instrument for measurement or testing an
electrical circuit, your _________ should be considered first:
a. personal safety
c. surrounding
b. theoretical knowledge
d. dress
967. A moving coil voltmeter has a scale which is:
a. linear
c. exponentially decreasing
b. exponentially increasing
d. none of the above
968. High AC voltages are usually measured with:
a. electrostatic voltmeters
b. voltmeter and current transformer
c. potential transformer and voltmeter
d. voltmeter and multiplier
969. Under normal operation, the instrument which will be at least
effective in indicating than an alternator may overheat because
it is overloaded as a/an:
a. voltmeter
c. wattmeter
b. ammeter
d. stator thermocouple
970. A moving coil instrument can be used to measure:
a. low frequency AC
c. direct current
b. high frequency AC
d. DC and AC both
971. Large currents in DC circuits are almost always measured with
a/an:
a. ammeter and multiplier
b. millivoltmeter and shunt
144
c. millivoltmeter and multiplier
d. current transformer and ammeter
972. For measuring voltage across an electrical load, you would
connect a/an:
a. ammeter across the load
b. voltmeter in series with the load
c. ammeter in series with the load
d. voltmeter across the load
973. Deflection of pointer of a permanent-magnet moving coil meter
for fixed currents is ____ flux density I the air gap between
magnetic pole shoes and coil:
a. directly proportional to
c. independent of
b. inversely proportional to
d. none of the above
974. You are required to check the pf of an electrical load. No pf
meter is available. You would use: a. a wattmeter
b. an ammeter
c. a voltmeter and an ammeter
d. a kW-Hr meter
975. Which of the following sets of AC instruments may be used to
find pf of a singe phase motor:
a. one voltmeter and one ammeter
b. one voltmeter and one phase rotation meter
c. one voltmeter and wattmeter and one ammeter
d. one voltmeter, one kWH meter an one ammeter
976. The resistance of a field coil may be correctly measured by
using:
a. a voltmeter and an ammeter
b. a Schering bridge
c. a Kelvin double bridge
d. a Maxwell bridge
977. A moving iron meter is useful for voltage measurement at
_______ frequencies:
145
a. very high
b. high
c. low
d. none of the above
978. The meter that is suitable for direct current only is:
a. moving iron type
c. electrodynamic type
b. permanent magnet type d. hot wire type
979. A cross connection between two conductor cable may be
located by use of a/an:
a. Ohmmeter
c. Varley loop
b. Carey Foster bridge
d. Kelvin bridge
980. A thermocouple instrument would be useful for current
measurement at _______ frequencies:
a. high
c. very low
b. low
d. none of the above
981. The hot-wire ammeter:
a. is used only for DC circuits
b. is a high precision instrument
c. is used only for AC circuits
d. reads equally on DC and/or AC circuits
982. You have been told by your foreman to measure the resistance
of some feeders. For this purpose, your would use: a. magneto
test
c. a bell test
b. a megger
d. none of the above
983. When connecting wattmeters to a load circuit consuming large
current, it is necessary to use:
a. potential transformers
c. power shunts
b. isolating transformers
d. current transformers
984. Which of the following instrument will be used to measure
alternating current only?
a. moving iron voltmeter
b. permanent magnet type ammeter
c. induction type ammeter
d. moving iron (attraction type) ammeter
146
985. For increasing the range of DC ammeters, you would use a/an:
a. inductance
c. shunt
b. capacitor
d. current transformer
986. A DC milliammeter may be used to measure voltages:
a. if a high external resistance s used in series with it
b. when a proper shunt is sued with it
c. by simply connecting it across the lines
d. provide a high external resistance I sued across its terminals
987. A millimeter can be used:
a. as a voltmeter
b. only as an ammeter
c. both as voltmeter and ammeter
d. none of the above
988. Which of the following is commonly used for extending the
range of an AC ammeter?
a. a current transformer c. a shunt
b. a capacitor
d. an inductance
989. A shunt is used in parallel with a DC ammeter measuring large
currents in order to:
a. reduce meter current
b. provide damping for meter pointer
c. protect meter against shorts
d. increase sensitivity of the ammeter
990. For testing and calibrating a polyphase KWH meter using a
single phase supply, the best method is to connect the:
a. current coils in series and voltage coils in parallel
b. voltage coils in series and current coils in parallel
c. voltage coils in parallel and current coils in parallel
d. voltage coils in series and current in parallel
147
991. A hot wire ammeter when used to measure the output current
of full wave rectifier will register _______ of the maximum
value of the rectified current:
a. 1.0
c. 0.353
b. 0.707
d. 0.637
992. When operating properly, a certain circuit requires a maximum
current of 10 A. Is a calibrated ammeter connected in the
circuit reds 13 A, it is possible that: a. one of the branch circuits
is open
b. a partial short exists somewhere in the circuit
c. the main ground connection is open
d. a high resistance connection exists somewhere in the circuit
993. A newly completed lighting equipment is always subjected to
high voltage test in order to:
a. check the dielectric strength of the insulation
b. measure insulation resistance of the wiring
c. make sure that the equipment will be able to withstand the
operating voltage
d. find the maximum voltage the equipment can withstand
994. A high voltage dielectric test performed on wires and cables is
primarily meant to check:
a. dielectric strength of the insulation
b. insulation resistance
c. ability of the insulation to withstand the voltage it is likely
to be subjected to when n service
d. moisture absorption quality of the insulation used
995. For proper connection of a single phase wattmeter to a circuit,
you should use two:
a. current leads only
b. current and two potential leads
c. potential leads only
d. current leads and two power leads
996. Which of the following instruments usually has lowest
resistance?
a. megger
c. voltmeter
b. frequency meter
d. ammeter
148
997. A megger is generally used to:
a. determine the speed of an electrical motor
b. measure resistance of a lightning cable
c. test a lighting circuit for ground
d. measure the amount of illumination
998. To measure the emf of a Weston standard cell, one would use
a/an:
a. moving coil voltmeter
c. galvanometer
b. electrostatic voltmeter
d. potentiometer
999. In the two wattmeter method of 3 phase power measurement
if both wattmeters read positive and equal values, then pf of
the load is:
a. 0
c. 0.5
b. unity
d. 0.866
1000. The ampere-hour (A-hr) is associated with:
a. rectifiers
c. electromagnets
b. transformer
d. storage cells
1001. Deflection sensitivity of deflecting pates of cathode ray tube
_______ the distance between deflection plates: a. is directly
proportional to
b. is inversely proportional to
c. does not depend on
d. none of the above
1002. If one of the two wattmeters used for measuring power taken
by a balanced three phase reads zero, then pf of the load is:
a. 0.866 lagging
c. unity
b. 0.5
d. zero
1003. One disadvantage of using a moving iron ammeter to measure
DC current is that:
a. its calibration gives rms value of current
b. it responds only to AC currents
149
c. its scale is even
d. its coil needs unmanageably large number of turns
1004. Signal injection/tracing is a method commonly used in
troubleshooting:
a. industrial wiring
c. residential wiring
b. electric motors
d. a radio
1005. The instrument often used for checking the degree of motor
shaft misalignment is:
a. a voltmeter
c. dial indicator
b. a clamp on an ammeter
d. megohmeter
1006. The frequency stability of a crystal oscillator depends upon:
a. crystal
b. tuned circuit
c. crystal as well as the tuned circuit
d. all of the above
1007. A 15 A fuse is found open
but has a choice between
a. 10 A fuse
b. 30 A fuse
and the servicer has no replacement
10 A and 30 A fuse. He should use:
c. either a and b
d. both a and b
1008. The type of thermostat commonly used in appliance with
heating element is:
a. circuit breaker
c. bimetallic
b. magnetic relay
d. thermocouple
1009. Hay bridge is usually used for measuring:
a. inductance
c. resistance
b. capacitance
d. all of the above
1010. Schering bridge is used for measurement:
a. inductance
c. capacitance
b. frequency
d. none of the above
1011. The Wein‟s bridge is particularly useful for measuring
frequencies of _____ value:
a. very high
c. low
150
b. high
d. all of the above
1012. Impedance relay is used to protect:
a. line beyond a particular zone
b. line within a particular zone
c. the whole transmission system
d. none of the above
1013. A current measuring instrument can be modified to measure
voltages by:
a. using thicker wire in the coil
b. using a high resistance shunt
c. adding resistance in series
d. adding resistance in parallel
1014. Buchholz relay is used in ______ protection:
a. generator
c. line
b. transformer
d. all of the above
1015. Two principal parts of a permanent magnet moving coil
(PMMC)
a. pivots and jewel bearings
c. case and iron ore
b. needle and scale
d. coil and magnet
1016. What is the purpose of providing a mirror behind the pointer in
measuring instruments?
a. the scale is illuminated through the mirror
b. with the help of the mirror it can be seen whether the pointer
is bent or not
c. the mirror is semi-transparent so as to allow the observation
of the interior of the instrument
d. reading errors due to inclined observation are eliminated by
removing parallax between the pointer and its image in the
mirror
1017. Meter accuracy is determined by:
a. half-scale deflection
151
b. full-scale deflection
c. one-fourth of full scale deflection
d. one-tenth of full scale deflection
1018. Threshold of sensitivity with respect to instruments is:
a. the maximum signal which can be measured
b. the value of sensitivity on the highest scale
c. the value of sensitivity on the lowest scale
d. the smallest signal that result in a detectable output
1019. On which of the following factors the sensitivity in accuracy of
an instrument does not depend?
a. hysteresis or dead bond
c. frequency response
b. amplitude distortion
d. all of these
1020. To increase the range of a voltmeter
a. a low resistance is connected in series
b. a low resistance is connected in parallel
c. a high resistance connected in series
d. a high resistance is connected in parallel
1021.Moving coil instruments are use
a. in AC circuits only
c. in DC only
b. both AC and DC circuits
d. for measuring voltage only
1022. Which of the following damping methods is common in moving
coil instruments?
a. air damping
c. spring damping
b. fluid damping
d. eddy-current damping
1023. A moving iron type has
a. a linear scale
b. a nonlinear scale
c. its deflection is directly proportional to the current
d. its deflection directly proportional to the voltage
1024. The function of a shunt in ammeter is usually
a. by pass the current
b. increase the current in the coil
152
c. decrease the voltage drop
d. increase the meter resistance
1025. The shunt resistance in an ammeter is usually
a. less than meter resistance
b. equal to meter resistance
c. greater than mater resistance
d. of any value
1026. A low voltage is measured on higher scale of voltmeter. The
instrument would have
a. low accuracy
c. low precision
b. low resolution
d. all of these
1027. An electrodynamic meter can be used to measure
a. AC voltage
b. DC voltage
c. DC as well as AC voltage
d. DC voltage but for AC voltages rectification is necessary
1028. A multimeter consists of
a. voltmeter and ohmmeter
b. voltmeter and current meter
c. current meter and ohmmeter
d. voltmeter, current meter and ohmmeter
1029.Megger is an instrument to measure
a. very low resistance
c. Q of a coil
b. insulation resistance
d. inductance of a coil
1030. Megger in its operation is based upon
a. moving coil meter
c. dynamic meter
b. moving iron meter
d. electrostatic meter
1031. Which of the following equipment is not a part of megger
a. hand crank
b. moving coil meter
153
c. a coil of high inductance
d. gear box generator
1032. Inductance is measured in terms of capacitance and
resistance by
a. Schering bridge
c. Maxwell-Wein bridge
b. Anderson bridge
d. Wein bridge
1033. The potentiometer wire should have
a. high specific resistance and high temperature coefficient
b. high specific resistance and low temperature coefficient
c. low specific resistance and high temperature coefficient
d. low specific resistance and low temperature coefficient
1034. A wattmeter can measure
a. AC power only
b. DC power only
c. AC as well as DC power
d. DC power and AC power after rectification
1035. A relay in which the measurement is performed by a stationary
circuit and which has no moving parts is known as a. static
relay c. instantaneous relay
b. differential relay
d. time relay
1036. While selecting a gas for circuit breaker, the property of gas
that should be considered is a. high dielectric strength
b. non-inflammability
c. non-toxicity
d. none of the above
1037.For high AC circuit breakers, the rated short circuit current is
passed for
a. 0.01 sec
c. 3 sec
b. 0.10 sec
d. 30 sec
1038. Which of the following is not a type of the contactor for circuit
breakers?
a. electro-magnetic
c. pneumatic
154
b. electro-pneumatic
d. vacuum
1039. There is definite objection to use of which of the following
medium for extinguishing the arc in case of a circuit breaker?
a. air
c. vacuum
b. SF6 gas
d. water
1040. In a circuit breaker, the active recovery voltage depends upon
a. power factor
c. circuit condition
b. armature reaction
d. all of the above
1041. A relay used for protection of motors against overload is
a. impedance relay
b. electromagnetic attraction type
c. c. thermal relay
d. d. Buchholz‟s relay
1042. A fuse wire should have
a. low specific resistance and high melting point
b. low specific resistance and low melting point
c. high specific resistance and high melting point
d. high specific resistance and low melting point
1043. The number of cycles in which a high-speed circuit breaker can
complete its operation is
a. 3 to 8
c. 20 to 30
b. 10 to 18
d. 40 to 50
1044. A material best suited for manufacturing of fuse wire.
a. Aluminum
c. Lead
b. Silver
d. Copper
155