Department of Electrical Engineering
Zeal COER Pune
FE(2019 course)
Subject : Basic Electrical Engineering [103004]
Insem Exam March 2021
Max marks : 30
Date: --.04.2021
Time: 01 hour
Instructions: Solve any 30 questions
Each question carries one mark
1) In case of electro-magnet --Flux direction can be reversed but field strength can not be altered
Flux direction can be reversed and field strength can be altered
Flux direction can not be reversed
Magnetic field strength can not be altered
2) In a magnetic circuit, MMF is…........
Directly proportional to the product of current and turns of the coil
Directly proportional to the ratio of current in conductor and turns of the coil
Directly proportional to voltage applied
Inversely proportional to the voltage applied
3) Every current carrying conductor placed in magnetic field will
Experiences force on the conductor
Induces voltage in a conductor
Conductor will become magnet
Conductor will be heated
4) Which is not the property of line of force ( magnetic Flux )
They always form closed path
They never cross each other
They generate from south pole and terminate at north pole
They are elastic in nature
5) According to Right Hand Gripping Rule, the thumb represents the direction of
Current
Magnetic field
Motion
Can not predict
6) According to Right Hand Gripping Rule, the curled fingers represents the direction of
Magnetic field
current
motion
Can not predict
7) According to Cork Screw Rule, while fitting the screw in batten, the direction of
advancement of screw indicates the
down word current
up word current
direction of magnetic field.
Can not predict
8) According to Cork Screw Rule, while removing the screw from batten, the direction of
screw indicates the
down word current
up word current
direction of magnetic field.
Can not predict
9) According to Cork Screw Rule, while fitting the screw in batten, the direction of rotation
of screw driver indicates the
down word current
up word current
direction of magnetic field in CW
Can not predict
10) According to Cork Screw Rule, while removing the screw from batten, the direction of
rotation of screw driver indicates the
down word current
up word current
direction of magnetic field in CCW
Can not predict
11) According to fleming’s left hand rule, the middle finger represents the direction of
Magnetic field
current
motion
Can not predict
12)
According to fleming’s Right hand rule, the index finger represents the direction of
Magnetic field
current
motion
Can not predict
13)
Inductance (L) of the electro-magnetic circuit is given by
14)
Amp-turm
Weber/turn
Flux linkage per ampere
Tesla
emf induced in a coil because of self / own changing flux is known as
Dynamically induced emf
Statically induced emf
Self induced emf
Mutually induced emf
15) emf induced in a conductor when magnetic field is stationary and conductor is moving
is known as
Dynamically induced emf
Statically induced emf
Self induced emf
Mutually induced emf
16)
When Two coils are tightly coupled, then coefficient of coupling 'K' is
Less than 1
Greater than 1
Equal to 0.5
Equal to 1
17)
When Two coils are magnetically isolated, then coefficient of coupling 'K' is
Less than 1
Greater than 1
Equal to zero
Equal to 1
18) Reluctance of the magnetic circuit is
Directly proportional to the cross sectional area
Directly proportional to the relative permeability
Inversely proportional to the length
Inversely proportional to the relative permeability
19) Flux density in magnetic circuit is measured in
meter / weber
Amp / meter
Tesla
weber / meter
20)
Certain coil has 200 turns and is carrying 5 ampere current, MMF of the coil is
200 amp-turn
1000 amp-turn
40 amp-turn
400 amp-turn
21) Soft iron electro-magnet has cross sectional area 10 square centimeter and has 0.8 mWb
flux, what will be the flux density in the core
8 Tesla
0.8 Tesla
1 Tesla
1.25 Tesla
22) A coil of 500 turns wound on soft iron piece produces 750 amp-turn , determine the current
in the coil
1.5 Amp
2 Amp
3 Amp
0.5 Amp
23) A coil of 100 turns is wound uniformly over a iron ring of 0.5 meter length and carry a
current of 2 Amp, what will be the magnetic field strength of the magnet
100 AT/m
200 AT/m
300 AT/m
400 AT/m
24) A coil consist of 1000 turns while carrying current of 10 Amp produces a flux of 1200
micro-weber, determine inductance of the coil
1.2 H
0.12 H
0.012 H
12 H
25) A current of 2 A through a coil sets up flux linkages of 0.8 Wb-turn. The inductance of the
coil is---0.8 H
0.4 H
0.2 H
1.2 H
26) If a current of 10A flowing through coil of self inductance 0.2H is uniformly reversed in 0.1
second. Find the induced emf.
20 V
40 V
80 V
10 V
27) If a current of 10A flowing through coil of self inductance 0.2H is interrupted in 0.1 second.
Find the induced emf.
20 V
40 V
80 V
10 V
28) The self inductances of two coils are 0.1 H & 0.5 H and mutual inductance between them
is 0.15 H. Find coefficient of coupling.
0.75
1
0.67
0.5
29) Which is a magnetic material?
copper
aluminium
silver
iron
30) unit of reluctance is
Henery
AT per Weber
weber -turn
Weber
31) What is the unit of absolute permeability?
Henery/meter
AT per Weber
weber -turn
Weber
32) The permeability of non-magnetic materials is
high
very high
medium
low
33) The flux in the magnetic circuit is-----permiance
directly proportional to
inversely proportional to
independent of
not related to
34) The inductance of coil is-----reluctance.
directly proportional to
inversely proportional to
independent of
not related to
35) The ability of a martial to carry the lines of flux is called as
permittivity
permeability
reluctance
resistance
36) Energy stored by a inductive coil is doubled when its current is increased by-----percent.
41.4
100
50
25
37) The_____ is reciprocal of the reluctance.
permittivity
permiance
reluctance
resistance
38) In simple series magnetic circuit having iron ring with one air gap , which statement is
correct.
Flux in air gap & iron remain same
mmf in air & iron remain same
Flux density in air gap & iron remain same
statement A & C
39) The m.m.f in magnetic circuit is analogous to ______in electric circuit.
current
emf
reluctance
resistance
40) The reluctance in a magnetic circuit is analogous to ______ in an electric circuit
current
emf
reluctance
resistance
41) The flux in a magnetic circuit is analogous to ______ in an electric circuit
current
emf
reluctance
resistance