2.SERIES CIRCUITS
1.What is the current flow through R1, R2, and R3?
a) 1A, 1A, 1A
b) 1A, 2A, 3A
c) 3A, 3A, 3A
d) 3A, 2A, 1A
Answer: Option A
Explanation:
V = IR
V = I(R1 + R2 + R3)
I = V/(R1 + R2 + R3)
= 9/(3 + 3 + 3)
= 9/9
= 1 Amp.
2.One of the most common applications of a potentiometer is as an
adjustable voltage divider, also known as
a) voltage control
b) current control
c) volume control
d) divider control
Answer: Option C
Explanation:
We know that potentiometer can be used for controlling both voltage and in
turn current which is nothing but adjusting the resistance value. In audio
power amplifiers, the speaker is connected to the load and this load
resistance must be a variable one so that we can the volume of the output
signal or sound.
3.If the resistance total in a series circuit doubles, current will:
a) be the same
b) be doubled
c) reduce source voltage
d) be halved
Answer: Option D
Explanation:
We know Ohm's law V=IR.
If R is doubled then.
V = I(2R).
then,
I= V/2R.
I=(1/2)(V/R).
Hence Current Halved.
4.Power is defined as:
a) the rate at which work is done
b) Work
c) the conversion of energy
d) Joules
Answer: Option A
Explanation:
ITS THE RATE OF DOING WORK..P=VI
5.What is the dc source voltage?
a) 78 V
b) 39 V
c) 13 V
d) 0 V
Answer: Option A
Explanation:
Ohm's Law: V = IR
Given
I = 0.013A;
R = R1+R2+R3 = (1+2+3) Kohm = 6 Kohm = 6000 ohm.
Therefore, V = 0.013 * 6000
= 78 volts
6.With a total resistance of 3300 ohms and a 45 V source, if R3 is
1200 ohms, what will be its voltage drop?
a) 16.36 V
b) 32.72 V
c) 10.90 V
d) 15.00 V
Answer: Option A
Explanation:
Total resistance= 3300 ohms
Total voltage=45V
R3= 1200 ohms
V3= total voltage*R3/total resistance
V3=45*1200ohms/3300ohms
V3=16.36V
A is the correct answer
7.Calculate the voltage at point B in the given circuit.
a) +10.48 V
b) +0.94 V
c) +2.6 V
d) +3 V
Answer: Option A
Explanation:
I=(12-9)/150= 0.02mA
let 9V as GND then Potential at B= (47+27)K * 0.02mA =1.48V
so pot. at B if GND is 0V =9V+1.48V =10.48V
8.In the given circuit, what type of failure will cause the voltage at
point B to equal the voltage at point C?
a) R1 shorts
b) R2 shorts
c) R1 opens
d) R2 opens
Answer: Option B
Explanation:
Here R2 will be short due to it voltage drop will be zero so voltage at point B
equal to point C. If R2 will open then voltage between B and C is equal to
between A and D.
9.
What is the voltage at points B to D in the given circuit?
a) +19.2 V
b) +8.8 V
c) +28 V
d) –19.2 V
Answer: Option A
Explanation:
Explanation:
As per the voltage Divider rule:
V= (R1 + R2) (Total Voltage/(R1+R2+R3))
V= (3.3K + 1.5K) (28/(2.2K + 3.2K + 1.5K))
V=19.2 V
10.
Calculate the voltage at point C in the given circuit.
a) +1.48 V
b) +0.94 V
c) +11.6 V
d) +3 V
Answer: Option C
Explanation:
I=(12-9)/150=0.02mA
voltage at B =9V + 0.2mA*(47+27+56)K ohm= 9V+2.6V= 11.6V
11.An 8-ohm resistor is in series with a lamp. The circuit current
is 1 A. With 20 V applied, what voltage is being allowed for the
lamp?
a) 4 V
b) 8 V
c) 12 V
d) 20 V
Answer: Option C
Explanation:
V(Lamp)+V(Resistor)=V(Total) (Total Potential=Sum of all potential
drops)
V(Resistor)=IxR
I=1A R=8ohms V(Total)=20V
V(Resistor)=1x8=8V
V(Lamp)=V(Total)-V(Lamp)
V(Lamp) = 20V-8V = 12V
12.What is wrong, if anything, with this circuit?
a) R1 is open
b) R1 is shorted.
c) R2 is open
d) R2 is shorted.
Answer: Option B
Explanation:
Consider a practical condition in your life.
When you entering into a Cinema hall which way you prefer first?
1)Exit in which all crowd are coming out in opposite to you.
2)Entrance no crowd is coming opposite to you.
obviously 2nd one right.
Same here in the case of current it goes in the way which offers very
less resistance.
Ammeter's internal resistance is very low so it acts as bypass circuit
path for current so R1 will be short circuited.
If instead of Ammeter there is Rheostat set for a high value more
current will be flowing through R1.
13.Kirchhoff’s voltage law states that:
a) the sum of the voltage drops in a series circuit is equal to the
total applied voltage
b) the algebraic sum of the resistances is equal to the sum of the
voltages
c) the algebraic sum of the individual currents around a closed
loop is zero
d) the voltages developed across each element in a series circuit
are identical
Answer: Option A
Explanation:
In any closed loop in a network, the algebraic sum of the voltage drops (i.e.
products of current and resistance) taken around the loop is equal to the
resultant electromotive force acting in that loop'
14.If series current doubles, then:
a) resistance is halved
b) voltage is doubled
c) voltage is reduced
d) resistance is doubled
Answer: Option A
Explanation:
R = V/I.
If I is doubled, then the equation becomes,
R = V/2(I) thus, 1/2 is the equivalent of the resistance.
15.What are the minimum and maximum output voltages?
a) 0 V, 4 V
b) 0 V, 8 V
c) 0 V, 12 V
d) 0 V, 16 V
Answer: Option D
Explanation:
Apply voltage divider rule i.e. vout = v1*(r2/r1+r2).
= 24*(10k/15k) = 16v.
16.A short circuit has:
a) too much resistance
b) no conductance
c) no resistance
d) low current
Answer: Option C
Explanation:
Current always flows in low resistance path, in short circuit current is
maximum. So resistance is minimum(0).
17.If three resistors of 1.5 kilohms, 470 ohms, and 3300 ohms are in
series with a 25-volt source, what is the total circuit current?
a) 210mA
b) 5.2mA
c) 4.7mA
d) .007mA
Answer: Option C
Explanation:
Here V=25V
Total resistance=1500+470+3300=5270 ohms
Total Current = V/I
= 25/5270 = 4.7 mA
18.What is the total power in the circuit?
a) 170 mW
b) 1.7 W
c) 17W
d) 170W
Answer: Option A
Explanation:
Total resistance(R) = 13.2K.
current I = V/R = 48/13.2K = 3.636mA.
Power = I^2xR.
P = (1.322x10^-5).(13.2K).
= 174mW = 170mW.
19.A string of resistors in a series circuit will:
a) divide the source voltage in proportion to their values
b) reduce the power to zero
c) cause the current to divide
d) increase the source voltage in proportion to the values
Answer: Option A
Explanation:
Series circuit is voltage divider
Parallel circuit is the current divider.
20.
While putting three 1.5 V batteries into a flashlight, you put
one in backwards. The flashlight will be ______________.
a) brighter than normal
b) dimmer than normal
c) off
d) the same
Answer: Option B
Explanation:
Consider the correct combination is (+- +- +-)
Since they did not mention which battery we are putting backwards,
We can assume three possible combinations i.e.
1 (+- -+ +-) here 1st two batteries nullify each other and acts as short
circuit so light will work only by the 3rd battery
2 (-+ +- +-) here also 1st two batteries nullify each other and acts as short
circuit so light will work only by the 3rd battery
3 (+- +- -+) here 2nd and 3rd batteries nullify each other and acts as short
circuit so light will work only by the 1st battery
So in all the three combinations the light will work only by one battery so the
light will be dimmer than normal
21.If a voltage is connected between contacts 2 and 3 in the given
circuit, which resistors will carry current?
a) All twelve resistors will carry current.
b) Only R6 and R11 will carry current.
c) Only R2, R4, R6, and R11 will carry current
d) Only R3, R6, R9, and R12 will carry current.
Answer: Option C
Explanation:
If voltage is applied to contact 2 which is connected to R6 from R6 it is
connected to R2 (see bottom board "/" connection) , R2 is connected to R4
(see top board) , from R4 to R11 (see bottom board).
22.Given a series circuit containing resistors of different values,
which statement is not true?
a) The current through each resistor is the same.
b) The sum of the voltage drops across each resistive element will
be equal.
c) The total resistance is the sum of the value of the resistors.
d) The voltage drop across each resistor is the same
Answer: Option D
Explanation:
In that series circuit, voltage drop of each resistor will be same if the resistor
values are equal.
23.With 20 V applied, an 8-ohm resistor is in series with a lamp.
When the lamp is removed, what voltage will be read across the
lamp socket?
a) 0 V
b) 8 V
c) 12 V
d) 20 V
Answer: Option D
Explanation:
Case 1: When lamp is in series with 8ohm resistor
Case 2: The lamp is removed from circuit and asking the drop across lamp
hoder.
Here when lamp is remove it is like circuit is open circuited at lamp place.
So the drop across open circuit will be equal to source voltage or we can
consider it also as drop across 8ohm resistor
Vr=(20/8)x8 = 20V
Drop = 20V
24.When 50 V is applied to four series resistors, 100 µA flows. If R1
= 12 k
, R2 = 47 k , and R3 = 57 k , what is the value of R4?
a) 38.4 k
b) 3.84 k
c) 384 k
d) 3.84 M
Answer: Option C
Explanation:
Rtotal = R1+R2+R3+R4.
= 12+47+57+R4.
= 116+R4.
V = IR.
R = V/I.
= 50/100*10^6.
= 500K.
500K = 116K+R4.
R4 = 384K.
25.In a series circuit, the voltage measured across a short will be:
a) source voltage
b) infinite voltage
c) zero volts
d) the normal voltage drop
Answer: Option C
Explanation:
Both points that we measure at have the same voltage so the voltage
measured equal zero because the difference in voltage is zero.
26.
Which is a true statement about the circuit in the given circuit?
1. The batteries are series-aiding and the total source voltage
equals 21 V.
2. The batteries are series-opposing and the total source voltage
equals 3 V.
3. The batteries are series-aiding and the total source voltage
equals 3 V.
4. The batteries are series-opposing and the total source voltage
equals 21 V.
Answer: Option B
27.When two persons push each other face to face who will win?
The one who pushes with more force or in other words one who
have more energy than other.
The resultant motion of two persons(current) will be in higher force
direction.
A series circuit current: remains the same through each component
is the same as the individual resistances is subtracted by each
component varies through each component
Answer: Option A
Explanation:
Current in Series circuit is like water coming from a simple tap.
Current in Parallel circuit is like water coming from a shower tap.
28.
a) +19.2 V
b) +8.8 V
c) +28 V
d) –19.2 V
Answer: Option C
Explanation:
When R2 is opened there is no current flow in the circuit.
So terminal voltage = Source Voltage
29.If 5 V and 16 V power supplies are connected in series-opposing,
what is the total voltage?
a) 11 V
b) 16 V
c) 21 V
d) 80 V
Answer: Option A
Explanation:
The batteries are series opposing than the total voltage is 11v.
30.What is the total resistance?
a) 0 k ; there is no current
b) 2 k ; the average
c) 3 k ; the largest
d) 6 k ; the sum
Answer: Option D
Explanation:
rt=r1+r2+r3
d is right answer.
31.Which equation determines individual resistor voltage drop?
a) V x R
b) I2 x R
c) V x I
d) I x R
Answer: Option D
Explanation:
V = I*R
32.How will an open resistor affect a series circuit?
a) Current will flow around the open resistor.
b) The open resistor will drop 0 V.
c) Total resistance will decrease.
d) No current will flow in the circuit.
Answer: Option D
Explanation:
Consider there are three bridges in your way to home.
Assume your travelling in car.
The cars are like current and bridges like resistors.
When one bridge is cut down how will your car reach home.
33.The voltage drop across a series resistor is proportional to what
other value?
a) total resistance
b) its own resistance
c) wattage rating
d) the amount of time the circuit is on
Answer: Option B
Explanation:
In series circuit current is same in all resistor so current is constant. V= IR.
VOLTAGE IS PROPORTIONAL TO TOTAL RESISTANCE.
34.Resistance in a series circuit will:
a) control the voltage
b) double the current
c) halve the power
d) oppose current
Answer: Option D
35.When a battery is connected to a series circuit, it delivers current
based only upon:
a) primary/secondary difference
b) total resistance
c) the polarity connections
d) average resistance
Answer: Option B
Explanation:
Total current in a series circuit = Total voltage/Total resistance.
Hence so answer is resistance and another thing is current is purely depends
on resistance.
36.What determines the total resistance in a series circuit?
a) the largest resistor
b) the sum of the resistors
c) the largest resistor minus the smaller
d) the smallest resistor
Answer: Option B
37.If two resistors have the same voltage drop in a series circuit, it
means:
a) they are connected in parallel
b) they are of unequal value
c) the voltage has doubled
d) they are of equal value
Answer: Option D
Explanation:
Voltage drop = IxR
In series circuit I is same in all resistor.
ie IxR1=IxR2
only if R1=R2
38.If series resistors dissipate 16 mW, 107 mW, 146 mW, and 243
mW, what is the total power consumed by the circuit?
a) 128 mW
b) 269 mW
c) 512 mW
d) 1024 mW
Answer: Option C
Explanation:
Total Power in series or parallel
P1+ p2+ p3+ p4+.....
So total disspation = 16m+107m+146m+243m=512mw.
39.A series circuit schematic is recognized because all the
components are connected:
a) diagonally across the page
b) in a uniform vertical manner
c) end to end in a "string"
d) horizontally across the page
Answer: Option C
40.With a 900 V source, voltage is divided across 3 series resistors
of 300 V, 280 V, and:
a) 30 V
b) 270 V
c) 320 V
d) 900 V
Answer: Option C
Explanation:
Source voltage = 900V
Current remain same for the whole circuit ; voltage differ
So,
300+280+x=900
x=900-580=320V
41.
How much current flows in the circuit in the given circuit?
a) 20
A
b) 60
A
c) 80
A
d) 140
A
Answer: Option A
Explanation:
Using kirchaff's law,In the circuit the current remains same. So, take it as I,
9-(47k+27k+56k+20k)*I-12=0
9-12-(150k)*I=0;
150K*I=3;
I=3/150K;
I(current) = 20 micro amps.
True/False
1.The total resistance of a series circuit is equal to the average of all
the resistance values.
True
False
Answer: Option B
Explanation:
Yes, the total resistance of a resistor is equal to the sum of all the resistance
values but not average of all resistance values.
2.The total resistance of a series circuit always depends on the
highest value resistor in that circuit.
True
False
Answer: Option B
Explanation:
It depends upon sum of all the resistance.
3.
If four 9 V batteries are connected series-aiding, the total voltage is
36 V.
True
False
Answer: Option A
4.The total resistance is 35
True
False
Answer: Option A
Explanation:
.
Since the resistors are in series so,
5 ohm + 10 ohm + 15 ohm + 5ohm = 35 ohm.
5.These components are in series.
True
False
Answer: Option A
6.In a series circuit, larger resistances drop larger voltages.
True
False
Answer: Option A
7.To find the total resistance in series, add the individual
resistances.
True
False
Answer: Option A
8.An open in a series circuit will cause maximum voltage across the
power supply terminals.
True
False
Answer: Option A
9.A short in a series circuit causes the total circuit current to
decrease.
True
False
Answer: Option B
Explanation:
Short in the series circuit the current flow itself wnt be there because of
short so the total circuit current wont decrease. So false.
10.Voltage sources are added when they are series-opposing.
True
False
Answer: Option B
Explanation:
Voltage sources are subtracted when they are series-opposing.
11.The total power dissipated in a series resistive circuit exceeds the
sum of the resistor powers.
True
False
Answer: Option B
Explanation:
Total power dissipated in a series resistive circuit is equal to the sum of the
resistor powers.
12.A series circuit provides only one path for current between two
points
True
False
Answer: Option A
13.Using a voltage divider the voltage across R1 is 10 V, R2 is 15 V,
and R3 is 30 V.
True
False
Answer: Option B
14.If 7.3 k , 1.8 k , and 4.9 k
total resistance is 14 k .
True
resistors are wired in series, the
False
Answer: Option A
15.The sum of the voltage drops across series resistors must equal
the total voltage applied.
True
False
Answer: Option A
Explanation:
Since in series voltages are equal.
Therefore,
Input voltage = output voltage drops.
16.The sum of all the voltage drops in a series circuit equals the
source voltage.
True
False
Answer: Option A
17.To find the total current in series, add the individual currents.
True
False
Answer: Option B
18.Ground is the reference point from which voltages are measured
in an electronic circuit.
True
False
Answer: Option A
19.The voltage across R1 is 10 volts.
True
False
Answer: Option B
20.In a series circuit, the current flowing out of a resistor won't
always equal the current flowing into that resistor.
True
False
Answer: Option B
21.As additional resistors are added to a series circuit, the total
circuit resistance increases.
True
False
Answer: Option A
Fill in the blanks
1.The ______ determines whether connected resistors are in series,
parallel, or series-parallel?
a) current flow
b) power source
c) voltage flow
d) wattage source
Answer: Option A
2.If a 3.9 k , a 7.5 k , and a 5.6 k
resistor are connected in
series with a 34 V source, the voltage dropped across the 7.5 k
resistor equals _____.
a) 34 V
b) 15 V
c) 7.8 V
d) 11.2 V
Answer: Option B
Explanation:
TOTAL R = 17 OHM
V = 34 V
THEN I = V/R = 34 / 17 = 2 AMP
NOW I = 2 AMP & R= 7.5 OHM
V = I*R = 2*7.5 = 15 v
3.
In the given circuit, R1 equals _____.
a) 100 k
b) 200 k
c) 300 k
d) More information is needed to find R1.
Answer: Option C
4.The total circuit power in the given circuit equals _____.
a) 64 µW
b) .4 µW
c) .0 W
d) 16 × 10–12 W
Answer: Option A
Explanation:
R(eq) = (1.2+1.8+1)M= 4M
I = V/R(eq)
= 16/4
= 4microAmp
P= I^2*R(eq)
= (4*10^(-6))^2*(4*10^6)
= 64microW
5.
In the given circuit, the voltage dropped across R3 equals ___.
a) 1.5 V
b) 3 V
c) 6 V
d) More information is needed to find the voltage dropped across
R3.
Answer: Option A
Explanation:
V(Drop) = I*R3.
I = V/(R+R2+R3).
R3 = V(Drop)/I.
6.If a 220
, a 100
, and a 180
resistor are connected in series
across a 12 V source, the circuit current equals ___.
a) 41.67 A
b) 120 mA
c) 500 A
d) 24 mA
Answer: Option D
Explanation:
Total resistance=220+100+180=500
voltage=12v
we know that
V=IR
there fore
I=V/R
I=12/500
I=24mA
7.If a 47
and a 68
resistance is ___.
a) 3,196
b) less than 47
c) less than 68
d) 115
Answer: Option D
resistor are connected in series, the total
8.
In the given circuit, R2 equals _____
a) 100 k
b) 200 k
c) 300 k
d) More information is needed to find R2.
Answer: Option B
Explanation:
Given voltage at R1 = 4.5v.
Voltage at R3 = i*R3 = (15*10^-6)*(100K) = 1.5v
Voltage at R2 = (9)-(4.5)-(1.5) = 3v.
R2 = v/i = 3/(15*10^-6) = 200K.
9.The polarity on the side of the resistor where current enters is
______. The polarity on the side of the resistor where current exits
is ___________.
a) positive, positive
b) negative, negative
c) negative, positive
d) positive, negative
Answer: Option C
10.A voltage divider is always a _____
a) series-parallel circuit
b) series circuit
c) parallel circuit
d) bridge circuit
Answer: Option B
11.If five equal resistors are connected in series with a 20 V source,
and a current of 400 µA is measured, each resistor equals ___.
a) 10 k
b) 50 k
c) 125 k
d) 20 k
Answer: Option A
Explanation:
R = 5R.
V= 20V.
I = 400*10^-6A.
SO WE KNOW THAT V = IR.
SO, 20 = 400*10^-6*5R.
So we will get it as R=10000.
That is, R = 10kohms.
12.If four 90
resistors are connected in series across an 18 V
source, the current equals ___.
a) 50 mA
b) 0.2 A
c) 5 A
d) 20 A
Answer: Option A
Explanation:
By Ohm's law, V = IR.
I = V/R
Given, Four 90 ohm resisters in series.
So, R = ( R1 + R2 + R3 + R4) = 4 x 90 = 360 ohms.
Therefore, I = 18/360 = 0.05 A [or] 50 milli amps.
13.–1.2 V, +15 V, and –6 V batteries are connected in series. The
magnitude of total voltage is _________.
a) 7.8 V
b) 10.2 V
c) 22.2 V
d) 1.3 V
Answer: Option A
14.
In the given circuit, _____ are in series.
R1 and R3
R3 and R5
R5 and R7
None of the above
Answer: Option B
Explanation:
in bottom one r3 connected to r9 then r9 connected to r12 again r12
connected to r5. So the answer is r3 and r5.
3.Parallel Circuits
1.When parallel resistors are of three different values, which has the
greatest power loss?
a) The smallest resistance
b) The largest resistance
c) They have the same power loss.
d) Voltage and resistance values are needed.
Answer: Option A
Explanation:
The resistors are in parallel & in parallel voltage is same but in parallel
current divides, current follows the low resistive path, so high pwr loss
occurs in small resistance. p = i^2*r.
2.What is the product-over-sum result of 150 and 6800?
a) 150
b) 146.7
c) 0.006
d) 6800
Answer: Option B
Explanation:
Formula of: product-over-sum r=(r1*r2)/(r1+r2)
r=(150*6800)/(150+6800)
r=146.7ohm
3.The voltage across any branch of a parallel circuit:
a) varies as the total current varies
b) is inversely proportional to total circuit resistance
c) is equally applied to all branch conductances
d) is dropped in proportion to each branch resistance
Answer: Option C
Explanation:
Voltage across parallel circuit are always same
The voltage across series branch is addition of all Voltages & in parallel
circuit is same, i.e. applied voltage.
from V=IR
(1) V=V1+V2=V3..... in series Ckt
(2) I=I1+I2+I3......in parallel Ckt
4.What is the total power loss if 2 k
resistors have an IT of 3 mA?
a) 6 W
b) 36 W
c) 6 mW
d) 36 mW
Answer: Option C
and 1 k
parallel-connected
Explanation:
Parallel Connection
Req = R1*R2/R1+R2.
Req = 2000*1000/2000+1000
= (2000/3000) ohms i.e (2/3)K ohms.
P = I^2 * Req.
= (3*10^-3)^2 * (2/3) * 10^3
= 9 * 10^-6 * (2/3) * 10^3
= 6 m Watts
5.What happens to total resistance in a circuit with parallel resistors
if one of them opens?
a) It increases
b) It halves.
c) It remains the same
d) It decreases
Answer: Option A
Explanation:
In parallel resistance the effective resistance value will be less than the
smallest valued resistance. For eg, if a 2 ohm and 3 ohm resistance are in
parallel effective resistance will be less than 2 ohm. So when one is opened
the effective resistance increases.
6.Components that connect in parallel form:
a) branches
b) open circuits
c) short circuits
d) a voltage divider
Answer: Option A
Explanation:
In the parallel circuit current will pass one by one branch of the connected
components, the Voltage will be same
7.A parallel circuit differs from a series circuit in that a parallel
circuit has
a) no path for current flow
b) fewer paths for current flow
c) one path for current flow
d) more than one path for current flow
Answer: Option D
In serial circuit Voltage is Different but current are same, But in parallel
circuit Voltage are same But current are different so in parallel circuit current
has many path for current flow
8.
In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to
the speakers. How much total current is the amplifier providing to
the speakers?
a) 0 A
b) 1.5 A
c) 3 A
d) More information is needed to find the total current provided to
the speakers
Answer: Option C
Explanation:
I=V/R.
For first speaker I=12/8=1.5A.
For second speaker I=12/8=1.5A.
Hence total current=1.5+1.5=3A.
9.If two parallel-connected resistors dissipate 6 watts and 10 watts
of power, then what is the total power loss?
a) 3.75 watts
b) 4 watts
c) 16 watts
d) 60 watts
Answer: Option C
Explanation:
Total Power in Series and Parallel resistive circuit will be addition of
individual powers:
Parallel: P = V^2/(R1||R2) = V^2/((R1*R2)/(R1+R2)).
= V^2/R1+V^2/R2 = P1+P2.
Series: P = I^2*(R1+R2) = I^2*R1+I^2*R2 = P1+P2.
Power is total of each component's individual power, irrespective of how
components are connected. (i.e. Series or parallel). So 6+10=16W is correct
answer.
Remember: Power is always additive.
10.Which component is shorted?
a) R1
b) R2
c) R3
d) R4
Answer: Option D
Explanation:
G is galvanometer and it measure current. 2.4 A is in the next G so no
current through the R1. Similarly, no current through R2, R3 and finally
whole current through R4. So R4 is short circuited and others are open
circuit.
11.
What would these meter readings indicate about the circuit in the
given circuit?
Meter Readings: I = 7.6 mA, V = 12 V
a) R1 is open.
b) R2 is open.
c) The fuse is open.
d) The circuit is operating normally
Answer: Option B
Explanation:
Case1 :When R1 is open,
then the effective resistance R = R2||R3
i.e. 5K||2K = 10/7 K
then current I = V/R = (12*7)/10K = 8.4 mA(Which is not correct ans i.e
7.6 mA)
Case2 : When R2 is open,
then the effective resistance R = R1||R3
i.e. 7.5K||2K = 30/19 K
then current I = V/R = (12*19)/30K = 7.6 mA(Which is d correct ans i.e 7.6
mA)
Case3: When the fuse is open,
then it is not possible to obtain voltage of 12 V
So the correct answer is option [b].
or
CONSIDER THE FOLLOWING:
In Parallel circuit, the current will differ and the voltage will remain same
across all the branches. In other words, the voltage across R1, R2 and R3
will be 12V each.
I1= 12/7.5K => 1.6mA
I2= 12/5K => 2.4mA
I3= 12/2K => 6.0mA
In above, the total current 7.6mA will take place correctly when only I1 and
I3 present *(since, I1 + I3 = 7.6mA).
Hence, R2 must be discarded/ remove from the circuit. In other words, R2 is
open.
12.
In the given circuit, Channel 1 of the stereo amplifier outputs 12 V to
the speakers. How much total power is the amplifier delivering to
the speakers?
a) 0 W
b) 18 W
c) 36 W
d) More information is needed to find the total power delivered to
the speakers.
Answer: Option C
Explanation:
p1=24*24/8=18
p2=24*24/8=18
total power=p1+p2=36
13.If a 1 k and a 2 k resistor are parallel-connected across a 12 V
supply, how much current is received by the 2 k resistor?
a) 4 mA
b) 6 mA
c) 8 mA
d) 12 mA
Answer: Option B
Explanation:
Since 1KOhm||2KOhm
therefore Req=2/3 KOhm.
now using Ohm's law
I=V/R
we get I=18A.
So current in 2KOhm = (1*18)/(1+2)=6mA.
14.
What does VS equal in the given circuit?
a) 0 V
b) 9 V
c) 27 V
d) More information is needed to find VS.
Answer: Option B
Explanation:
voltage across the parallel resistors are equal.So votage Vs equals to the
voltage across R3 resistor..
15.The current through R1 will be:
a) 128 mA
b) 88 mA
c) 48 mA
d) 2.2 mA
Answer: Option C
Explanation:
Voltage across parallel resistors are same.
So voltage across R1 is 48v,
We Know i=v/r.
=48mA.
16.The voltage read by the voltmeter will be:
a) 24 V
b) 12 V
c) 6 V
d) 4 V
Answer: Option B
Explanation:
Voltage across parallel resistor will be same.
17.Which component is of the wrong value?
a) R1
b) R2
c) R3
d) R4
Answer: Option A
Explanation:
Given total power=9.408
Power of r1=48/1*1000=.48mW
r2=48/2*1000=.24mW
r3=48/3*1000=.16mW
r4=48/4*1000=.12mW
Total power = 1W
But the total power given=9.408W.
ie, one resistor is wrong value.
0.012A is current through R4
I R4= 48/4*1000 = .012A
So R4 is correct value
0.053 is the current total through r2, r3 and r4 as branch current total.
We know that current through R4=.012
I (R2+R3) = V/(R2*R3/R2+R3)
=48/(2*3/2+3)1000
=48/(6/5)1000
=48/1200
=.04
Then I(R2+R3+R4)= .04+.012 = .052
So that R2,R3,R4 are correct.
i.e. R1 is wrong
18.
What does I3 equal in the given circuit?
a) 5 mA
b) 45mA
c) 50mA
d) 100mA
Answer: Option A
Explanation:
i=v/r
i3= 9/1.8*10^3
i3= 5*10^-3
i3 = 5ma
19.What is the total power of the circuit?
1. 2.2 W
2. 4.2 W
3. 6.2 W
4. 8.2 W
Answer: Option B
Explanation:
Equivalent resistance of the circuit R = R1||R2||R3
R = 1K||2K||3K = 6/11 K
Power P = V2/R = (48*18*11)/6K = 4.224 mA
20.What are the individual values of two parallel resistors whose RT
is 8 ohms, when one has double the resistance of the other?
a) 2.7 ohms and 5.3 ohms
b) 8 ohms and 16 ohms
c) 10 ohms and 20 ohms
d) 12 ohms and 24 ohms
Answer: Option D
Explanation:
Let R1 be x, so R2 is 2x
8=(x*2x)/(x+2x)
So x is 12
Hence R1 is 12 and R2 is 24
21.When a parallel 5 k resistor and a 25 k
supply, what is the total power loss?
a) 2.4 mW
b) 3.3 mW
c) 24 mW
d) 33 mW
Answer: Option C
Explanation:
Since resistors are parallel so RT will be
1/RT = 1/R1 + 1/R2
1/RT = 1/5 + 1/25 = 6/25
RT = 25/6 or 4.16K
resistor have a 10 V
I = V/R = 10/(25/6) = 2.4 mA
So P = VI = (10)(2.4)= 24 mW
22.In a parallel resistive circuit:
a) there is more than one current path between two points
b) the voltage applied divides between the branches
c) the total branch power exceeds the source power
d) the total circuit conductance is less than the smallest branch
conductance
Answer: Option A
Explanation:
In parallel circuit voltage is same, so there must be changes occur in current
only i.e more than one current.
23.What is the total resistance?
a) 7 k
b) 1 k
c) 706
d) 353
Answer: Option D
Explanation:
1/rt=(1/1k)+(1/2k)+(1/3k)+(1/1k)=0.001+0.0005+0.0003+0.001=0.0028
r=353 ohm
24.Kirchhoff's current law for parallel circuits states that the:
a) sum of all branch voltages equals zero
b) total circuit resistance is less than the smallest branch resistor
c) sum of currents into a junction is equal to the difference of all
the branch currents
d) sum of the total currents flowing out of a junction equals the
sum of the total currents flowing into that junction
Answer: Option D
Explanation:
KCL denotes that Sum of incoming current is equal to sum of outgoing
current. In a parallel circuit all branch voltages are equal.
25.Which component is open?
a) R1
b) R2
c) R3
d) R4
Answer: Option C
Explanation:
It=I1=0.021A
I3=0.003A
IR1=12/1K=0.012A
IR2=12/2K=0.006A
IR3=12/3K=0.004A
IR4=12/4K=0.003A
here we can see that IR4=I3 (0.003A) ie no current is flowing through R3
Also It=IR1+R2+IR3+IR4=0.012+0.006+0.004+0.003=0.025 Which is
not correct.
By open circuiting R3 we get It=0.012+0.006+0.003=0.021 which is
correct.
So R3 is open in the circuit
26.
What would these meter readings indicate about the circuit in the
given circuit?
Meter Readings: I = 0 mA, V = 0 V
a) R1 is open
b) R2 is open
c) The fuse is open
d) The circuit is operating normally
Answer: Option C
Explanation:
If fuse would b closed then there would have some current, voltage as
current and voltage is given zero it is obvious that fuse is open.
27.If 550 mA of current leaves a node that had 250 mA entering
from one branch, how much current would enter from the other?
a) 250 mA
b) 300 mA
c) 550 mA
d) 800 mA
Answer: Option B
Explanation:
I1-I2=550-250=300
28.What would these meter readings indicate about the circuit in the
given circuit?
Meter Readings: I = 10 mA, V = 12 V
a) R1 is open.
b) R2 is open.
c) The fuse is open.
d) The circuit is operating normally
Answer: Option D
Explanation:
Now we should know total current.
it=vt/rt
1/rt=(0.00013)+(0.0002)+(0.0005)=0.00083=1204.8196 ohm
it=9.9 ma
The circuit is operating normally
29.
What does RT equal in the given circuit?
a) 90
b) 180
c) 200
d) 1.8K
Answer: Option A
Explanation:
r1=9/50ma=180 ohm
r2=9/45ma=200 ohm
r3=1800 ohm
1/rt=(1/180)+(1/200)+(1/1800)=0.00555+0.005+0.00055=0.0111=90
ohm
30.What procedure should be followed when troubleshooting with
an ammeter or voltmeter?
a) Short the leads and adjust
b) Check the meter’s external power supply
c) Start with the highest scale and adjust down to a lower scale.
d) Start with the lowest scale and adjust up to a higher scale.
Answer: Option C
Explanation:
An accurate circuit have to work properly with a sudden (considered as
sudden because it is the initial input) high power, as a non accurate system
can also give expectable output with low power.
31.A parallel circuit is also used as a divider for:
a) conductance
b) voltage
c) power
d) current
Answer: Option D
Explanation:
Voltage remains same and current gets divided into the branches in parallel
circuit.
32.What is RT for a 12 k
a) 1.5 k
b) 2 k
c) 6.3 k
d) 19 k
Answer: Option A
,a4k
, and a 3 k
resistor in parallel?
Explanation:
In case of parallel circuits resistance can be calculated using
1/RT=1/R1+1/R2+1/R3
from this,
we get
1/RT=1/12+1/4+1/3=2/3
RT=3/2k
=1.5k
33.What is the total resistance of four 1 k
resistors?
a) 200 ohms
b) 250 ohms
c) 400 ohms
d) 4 kilo ohms
Answer: Option B
parallel-connected
Explanation:
The total resistance(1/R) = 1/1+1/1+1/1+1/1
1/R = 4/1 -: R = 1/4 K Ohms
= 0.250 K Ohms
R = 250 Ohms
34.Which are the better test devices used to isolate a suspected
open component within a parallel circuit?
a) a voltmeter or an ohmmeter
b) neither an ammeter nor a voltmeter
c) a wattmeter or a voltmeter
d) an ammeter or an ohmmeter
Answer: Option D
Explanation:
Logic:.
If short circuit:current is max.
If open circuit:current is min (almost zero).
So.
Voltmeter & wattmeter cannot give any value when open circuited.
The devices used are ammeter and ohmmeter.
35.
What does P2 equal in the given circuit?
a) 45 mW
b) 405 mW
c) 450 mW
d) 900 mW
Answer: Option B
Explanation:
POWER=VOLTAGE*CURRENT
V1=V2=V3;
P2=V3*I2;
P2=45*10^-3*9
=0.405
=405mW
36.
What does R1 equal in the given circuit?
a) 90
b) 180
c) 200
d) 1.8 k
Answer: Option B
Explanation:
r=v/i=9/50*10^-3
(9*1000)/50
9000/50
900/5
180*5=900
37.What is the total resistance?
a) 1.045 k
b) 1.545 k
c) 2.045 k
d) 2.545 k
Answer: Option B
Explanation:
Power as seen on wattmeter = 1.491W
Voltage =48V
As we know P=V^2/R
By this relation we get R=1.545 Kohm
38.What is RT for fifteen 2 M
a) 133 k
b) 300 k
c) 750 k
d) 30 M
Answer: Option A
resistors all connected in parallel?
Explanation:
We know that.
1/RT = 1/R1+1/R2+1/R3.......1/Rn.
Then RT for fifteen 2 Mohm
1/RT = 1/R1+1/R2+1/R3.......1/R15
Here R1=R2=R3=......R15 = 2.
Therefore 1/RT = 1/2+1/2+1/2+....1/2(for fifteen time).
Take common 1/2.
Now 1/RT = 1/2(1+1+1+1+1....1(for fifteen time).
1/RT = 1/2(15) = 15/2.
Therefore RT = 2/15 = 0.133Mohm.
Now convert Mohm into kohm.
So Ans. 133 kohm.
39.Which is considered to be the common reference for a parallel
circuit?
a) Voltage
b) Current
c) Power
d) Resistance
Answer: Option A
Explanation:
Voltmeter is always connected in parallel.
True/False
1.The total resistance in a parallel circuit is always less than the
least resistor.
True
False
Answer: Option A
Explanation:
The total resistance in a parallel circuit is always less than the least
resistance. For example, we have two resistances in series as 2 ohm and 3
ohm. Then the total resistance of the parallel combination would be
(2*3) / (2+3) = (6/5) = 1.2.
2.If a branch opens in a parallel circuit, the current in the remaining
parallel paths will change
True
False
Answer: Option A
Explanation:
Current will change because voltage in the parallel branch remains same.
3.If a branch opens in a parallel circuit, the total circuit resistance
decreases.
True
False
Answer: Option B
Explanation:
Open circuit means I=0 & r=Infinity; Rt = r1*r2%r1+r2 then finally Rt
becomes infinity.
4.The largest branch resistance in a parallel circuit carries the
largest branch current.
True
False
Answer: Option B
Explanation:
Because current inversely proportional to resistance I=V/R
5.If two equal resistors are connected in parallel, they will carry
identical currents.
True
False
Answer: Option A
Explanation:
In parallel circuit Vt = v1=v2=v3.
So, if r1=r2 then i1=i2=v/r1.
6.Kirchhoff's current law states that the current flowing into a point
of a circuit is equal to the sum of the voltages in the output
branches.
True
False
Answer: Option B
Explanation:
KCL : States that sum of current flowing into a point of a circuit is equal to
the sum of the current in the output branches.So the above statement is
false.
7.The voltages across all components in parallel are equal.
True
False
Answer: Option A
8.The total resistance in a parallel circuit is always greater than the
lowest-value branch resistor
True
False
Answer: Option B
9.A parallel circuit is sometimes called a current divider.
True
False
Answer: Option A
11.The voltage in a parallel circuit is the same across each branch of
the circuit
True
False
Answer: Option A
12.The total power dissipated is 4.8 watts
True
False
Answer: Option B
Explanation:
Current through 1000 Ohms = 48/1000 = 0.048.
Current through 3000 Ohms = 48/3000 = 0.016.
Current through 5000 Ohms = 48/5000 = 0.0096.
Current through 8000 Ohms = 48/8000 = 0.0796.
Total Current is 0.0796 mA Therefore power dissipated is 0.0796 mA*48V =
3.8208.
13.If one branch shorts out in a parallel circuit, the other branches
are not affected
True
False
Answer: Option B
Explanation:
If the one branch is shorted then the current will flow through low resistance
path. I. E all current flow through shorted branch and will effect the other
branch.
14.If one of the resistors opens in a parallel circuit branch, the total
resistance of the circuit will decrease.
True
False
Answer: Option B
15.The total current entering a junction may be different from the
total current leaving the junction
True
False
Answer: Option B
16.The total resistance is 480
.
True
False
Answer: Option A
17.The total power in a parallel circuit equals the sum of the
individual branch powers
True
False
Answer: Option A
Explanation:
Since voltage is equally divided among the parallel branches, each element
in the branch absorbs power. Ex house hold networks
18.Current divider predicts that the most current will flow in the
parallel path of the most resistance
True
False
Answer: Option B
19.The total resistance of like value resistors in parallel is equal to
the value of the resistors multiplied by the number of resistors used.
True
False
Answer: Option B
Explanation:
If n resistors each of value are are connected in parellel then equivalant
resistance ic R/n
20.Parallel circuits have only one path for current
True
False
Answer: Option B
Explanation:
Parallel current divided at branches, so we cant say that parallel circuits
have only one path
Fill in the blanks
1.
The total current in the given circuit equals _____
a) 86 mA
b) 170 mA
c) 42 mA
d) 128 mA
Answer: Option B
Explanation:
According to kcl law
incoming current = outgoing current
hence
I total = I1+I2;
so the ans is 170mA
2.As additional resistors are connected to a parallel circuit, the total
resistance will ___
a) increase
b) increase by the value of the resistor being connected
c) decrease
d) remain unchanged
Answer: Option C
Explanation:
It will decrease only because whenever we added resistors in parallel
resistance value decreases.
3.An ammeter is connected in ______ with the branch resistor to
measure branch current, and in ______ with the voltage supply to
measure total parallel circuit current
a) parallel, series
b) series, parallel
c) series, series
d) parallel, parallel
Answer: Option C
4.
The total current in the given circuit is ___
a) 2.5 mA
b) 0.6 mA
c) 1.5 mA
d) 0.4 mA
Answer: Option A
Explanation:
In the above 12v is same for each branch of parallel circuit
I(total)=I1+I2+I3
So I1=12/20=0.6 mA
I2=12/8=1.5mA
I3=12/30=0.4mA
Total current I(total)=0.6+1.5+0.4=2.5 mA
5.
If the voltmeter indicates 12 V in the given circuit, the voltage
across R2 equals ___.
a) 12 V
b) VS minus 12 V
c) 0 V
d) More information is needed to find the voltage across R2
Answer: Option A
Explanation:
Since the 2 resistors are in parallel volage across them is the same=
12volts.
6.An ammeter is connected in ______ with the branch resistor to
measure branch current, and in ______ with the voltage supply to
measure total parallel circuit current.
parallel, series
series, parallel
series, series
parallel, parallel
Answer: Option C
7.Circuit analysis should reveal that the largest resistance in a
parallel circuit has the ______
a) least current
b) most current
c) least voltage
d) most voltage
Answer: Option A
8.An open resistor in parallel will cause the total ___ to increase
a) voltage
b) current
c) resistance
d) power
Answer: Option C
Explanation:
here resistor is open, so total resistance would increase. Current cannot flow
in an open ckt, so current would b same.
9.
The total power in the given circuit is ___.
4.8 mW
a) 4.8 mW
b) 18 mW
c) 7.2 mW
d) 30 mW
Answer: Option D
Explanation:
p = vi.
v = i*r therefore p=(v^2)/r.
Total resistance = (1/20k)+(1/8k)+(1/30k) = 4.8k ohm.
p = (12*12)/(4.8K) = 30mW
10.
The total resistance in the given circuit is _____
greater than 8 k
58 k
4.8 k
greater than 30 k
Answer: Option C
Explanation:
20k||8k||30k|| resister
Req=(160*30)k/(240+600+160)k
Req=4.8k ohms
11.
If R1 opens in the given circuit, the total current equals ___
a) 86 mA
b) 170 mA
c) 42 mA
d) 128 mA
Answer: Option D
Explanation:
According to kcl law I=I1+I2;.
When open i1=0; hence total current is 128mA
12.
If R2 opens in the given circuit, the voltage across R1 will ___
a) Increase
b) Decrease
c) equal 0 V
d) remain unchanged
Answer: Option D
Explanation:
The resistors are connected in parallel.
So in the parallel connection voltage remains unchanged
13.A parallel resistor's value that changes with age will cause a
corresponding change in ______
a) branch current
b) branch voltage
c) both branch current and branch voltage
d) power supply voltage
Answer: Option A
14.A circuit is parallel between two points if ___ between those two
points
a) the voltage divides
b) more than one current path exists
c) all resistors are equal
d) there is only one current path
Answer: Option B
4.SERIES-PARALLEL CIRCUITS
1.What theorem replaces a complex network with an equivalent
circuit containing a source voltage and a series resistance?
a) Multinetwork
b) Norton
c) Thevenin
d) Superposition
Answer: Option C
Explanation:
Thevenin theorem states that any complex n/w can be replaced by is
equivalent circuit containing a source voltage and a series resistance
2.What is the power dissipated by R2, R4, and R6?
a) P2 = 417 mW,
b) P2 = 407 mW,
c) P2 = 397 mW,
d) P2 = 387 mW,
Answer: Option A
P4
P4
P4
P4
=
=
=
=
193
183
173
163
mW,
mW,
mW,
mW,
P6
P6
P6
P6
=
=
=
=
166
156
146
136
mW
mW
mW
mW
Explanation:
By mesh analysis inspection method:
11 I1 - 8 I2 = 111 --> EQN 1.
-8 I1 + 17 I2 - 7 I3= 0 --> EQN 2.
-7 I2 + 14 I3 = 0 --> EQN 3.
BY RESOLVING THESE EQUATIONS WE GET,
I1 = 17.72 mA
I2 = 10.50 mA
I3 = 5.25 mA
Current through R2 is I1-I2 = 7.22 mA.
And by P = (I^2)R formula we can calculate power across the resistor R2
P = 7.22*7.22*10^-6*8*10^3 = 417 mW
3.
If the load in the given circuit is 120 k
voltage?
a) 15.79 V
b) 16 V
c) 4.21 V
d) 19.67 V
Answer: Option B
, what is the loaded output
Explanation:
Step 1:Find parallel combination of 8K & 120K = 7.5K
Step 2:Now 2k &7.5k are in series so total resistance=9.5k
Step 3:Find ct I=20v/9.5k= 2.105mA,
Step 4:find drop across 2K is 2.105m*2K=4.2V
Step 5:Finally Vl=20-4.2=15.8v.
4.In a series–parallel circuit, individual component power
dissipations are calculated using:
a) individual component parameters
b) a percent of the voltage division ratio squared
c) total current squared multiplied by the resistor values
d) a percent of the total power depending on resistor ratios
Answer: Option A
It will depend upon component parameter because if we take two resistance
values are 20 ohms and 100k.power dissipation= v*i
v=i*r
then p=i*i*r
so p is proportional to component parameter
In 20ohms resistor power dissipation less than 100k
5.The current flowing through an unloaded voltage divider is called
the:
a) resistor current
b) load current
c) bleeder current
d) voltage current
Answer: Option C
Explanation:
In electronics, a bleeder resistor is a resistor connected in parallel with the
output of a high-voltage power supply circuit for the purpose of discharging
the electric charge stored in the power supply's filter capacitors when the
equipment is turned off, for safety reasons
6.When a Wheatstone bridge is in a balanced condition, the center
voltmeter in the bridge will read:
a) twice the source voltage
b) the same as the source voltage
c) zero volts
d) half the source voltage
Answer: Option C
Explanation:
In the balanced condition difference will be zero and that's why the
voltmeter reading zero
7.When a load is connected to a voltage divider, the total resistance
of the circuit will
a) decrease
b) double
c) increase
d) remain the same
Answer: Option A
Explanation:
Voltage divider is when resistance is connected in series.. And when load is
connected to existing resistance in series then total resistance will be
increased
8.With 21 V applied, if R1 = 5 ohms, R2 = 35 ohms, and R3 = 14
ohms, what is the current of R2 if R1 is series connected with parallel
circuit R2 and R3?
a) 200 mA
b) 800 mA
c) 600 mA
d) 400 mA
Answer: Option D
Explanation:
1st calculate the total Resistance.
Rt = R1+R2||R3.
= 5+(35*14)/35+14 = 15.
According to voltage divider:
Voltage across R1 is V1 = v*R1/Rt.
V1=21*5/15=7.
Then voltage across the parallel circuit is 21-7=14;
Then current across I2 = 14/R2 = 14/35 = 0.4 A or 400 mA.
9.What is the total resistance of a circuit when R1 (7 k ) is in series
with a parallel combination of R2 (20 k ), R3 (36 k ), and R4 (45 k
)?
a) 4 k
b) 17 k
c) 41 k
d) 108 k
Answer: Option B
Explanation:
RT = R1 + ( 1/R2 + 1/R3 + 1/R4)
= 7+(1/20 + 1/36 + 1/45)
=7+(10)
=17 Kohms
10.
If the load in the given circuit is 80 k
current?
a) 196
A
, what is the bleeder
b) 1.96 mA
c) 2 mA
d) 2.16 mA
Answer: Option B
Explanation:
Find the total resistance which will be = 9.2kohm
Total current is =2.15mV
Bleeder current is current through resistor R2 which is= 1.96mA
Use the formula current through r2= rL/(r2+rL)
(80/88)*2.15 = 1.95454545
Here bleeder current is the current on R2 in the absence of load resistor RL.
It means bleeder current is the unloaded current on the specific resistor
where load is to be connected.
11.
What is the total resistance of the given circuit?
a) 92
b) 288
c) 17.7
d) 128
Answer: Option A
Explanation:
80||60||80=24
and
so tot re=24+68=92
12.What are the branch currents I2 and I3?
a) I2 = 4 mA, I3 = 2 mA
b) I2 = 4.5 mA, I3 = 2.5 mA
c) I2 = 2.5 mA, I3 = 1.5 mA
d) I2 = 5.5 mA, I3 = 3.5 mA
Answer: Option C
Total resistance of the circuit is:
4K+(12.5K||7.5K) = 4K+4.6875k) = 8.6875K.
Total current = 35/8.6875K = 4.028776 mA.
I2 = 12.5K*4.028776 mA/(20K) = 2.517985 mA.
I3 = 7.5K*4.028776 mA/(20K) = 1.510791 mA.
Hence none of the options above are correct.
13.If the load in the given circuit is open, what is the unloaded
output voltage?
a) 0 V
b) 4 V
c) 16 V
d) 20 V
Answer: Option C
Explanation:
Find the current in the circuit:
Add R1 & R2 which are in series.
R1+R2 = 10 kohm.
Current, I = 2 m amps.
Since vout is taken,
V = IR1.
V = 2m*2k.
V = 4V.
Therefore Vout = 20-4 = 16V.
14.What is the total resistance?
a) 2.2 k
b) 3.2 k
c) 4.2 k
d) 5.2 k
Answer: Option B
Explanation:
r11+r12;
ans||r6;
ans+r5;
ans||r4;
ans||r3;
ans+r2;
ans||r1=3.19k
15.
How much voltage is dropped across R3 in the given circuit?
a) 46 V
b) 34 V
c) 23 V
d) 12 V
Answer: Option D
Explanation:
Parallel resistance along R2,R3,R4=24
Total resistance= R1+(R2||R3||R4) =92
Total current= (v/i)= 46/92 =0.5A
Voltage drop across R3= 24*0.5= 12v
16.When placed into a circuit, how are electronic components
usually connected?
a) positive terminal to positive terminal
b) in parallel
c) as a combination of series and parallel
d) in series
Answer: Option C
17.
If the load in the given circuit is 12 k
voltage?
a) 5.88 V
b) 14.12 V
c) 16 V
d) 17.14 V
Answer: Option B
Explanation:
Total resistance=2+((12*8)/(12+8))=6.8
Total current 20/6.8 =2.94mA
Current through rl=(8/(12+8))*2.94=14.12
, what is the loaded output
19.What is the voltage to the load?
a) 11.4 V
b) 12.4 V
c) 13.4 V
d) 15.4 V
Answer: Option D
Explanation:
R2 is parallel to RL & in series with R1=7.155
total current is 35/7.155=4.895
current division rule in between r2& RL4
4.895*7.8/7.8+5.3=2.9
now voltage drop in RL is
2.9*5.3=15.4v
20.The first goal to accomplish in analyzing a complex series-parallel
circuit is to
a) equate all parallel components
b) equate all series components
c) solve for all the voltage drops
d) solve for the total current and resistance
Answer: Option D
21.
Which circuit fault do the meter readings in the given figure
indicate?
a) The 1 k
resistor is open
b) The 4.7 k
resistor is open
c) The 2.2 k
resistor is open
d) The 3.3 k
resistor is open
Answer: Option B
Explanation:
1) If 1 k opened no current will flow.
2) If 4.7 k opened 1st reading is correct. Now apply voltage divider rule..i.e.
3) 3/(3.3+1)*10 = 7.67 v which is also correct. So option B is correct.
22.
How much current is flowing through R1 in the given circuit?
a) 0.3 A
b) 0.15A
c) 0.5A
d) 0.68 A
Answer: Option C
Explanation:
(R2//R3//R4)are in parallel=24,
R1&(R2//R3//R4)are in series(68+24=92),
So I=(V/R)(46/92=0.5A)
Current through R1 also 0.5A because R1&(R2//R3//R4)are in series ( in the
series circuit current is same)
23.If R1 is in series with parallel connected to R2 and R3, what
happens to total current if R2 opens?
a) increases
b) decreases
c) remains the same
d) cannot tell
Explanation:
If resistors are in parallel and one is open the total resistance Will increase
hence current will decrease.
24.The first goal(s) to accomplish in analyzing a complex series–
parallel circuit is to:
a) equate all parallel components
b) equate all series components
c) solve for all the voltage drops
d) solve for the total current and resistance
Answer: Option D
25.If a series–parallel circuit has all 30-ohm resistors, what is the
total resistance when R1 is in series with a parallel circuit consisting
of R2 and R3?
a) 10 ohms
b) 20 ohms
c) 45 ohms
d) 90 ohms
Answer: Option C
Explanation:
R= R1+ R2*R3/R2+R3
R= 30+30*30/30+30
R= 30 ohm + 15 ohm
R=45 ohm
26.Components or combinations of components with common
currents, in a series–parallel circuit, are in:
a) parallel with each other
b) series with each other
c) either series or parallel with each other
d) none of the above
Answer: Option C
27.What determines if resistor connections are in series, parallel, or
series–parallel?
a) the voltage source
b) the power source
c) Resistance
d) current flow
Answer: Option D
28.What is the total resistance?
a) 800
b) 1.2 k
c) 1.6 k
d) 1.8 k
Answer: Option D
Explanation:
R=2k+1k+1/2k+1/1k+4k+1/3k
=1.8 {d}
29.If R1 is in series with a parallel combination of R2, R3, and R4,
when the resistance value of R2 increases, the voltage across R3 will
a) increase
b) decrease
c) remain the same
d) Cannot tell
Answer: Option A
Explanation:
Voltage should be same means that the voltage is same across r2 r3 and r4
but this constant value may increase or decrease by varying the value of
resistance i.e. v=IR.
30.A Wheatstone bridge can be used to determine an unknown
a) Current
b) resistance
c) power
d) Voltage
Answer: Option B
31.
Which circuit fault do the meter readings in the given figure
indicate?
a) The 1 k
resistor is shorted.
b) The 4.7 k
resistor is shorted
c) The 2.2 k
resistor is shorted
d) The 3.3 k
resistor is shorted
Answer: Option D
Explanation:
If 3.3k is shorted then all current will flow through it (as current takes path
with minimum resistance).
Hence no current flow through 2.2k resistor and no voltage drop across it.
32.In a series–parallel circuit consisting of R1 and R2 in series and
connected in parallel with R3, if R1 opens, then R2's voltage will:
a) Increase
b) decrease
c) remain the same
d) cannot tell
Answer: Option B
Explanation:
If we take r1=2, r2=3 & r3=4
Then,
r1+r2 = 5 //With r3 find value total resistance.
RT = 2.22.
Image current flow is 1 amp.
Then voltage is V = ir = 1*2.22 = 2.22 v.
If r1 is open, then find voltage r2/r3 = 1.714.
Current is 1 amp.
So V = IR =1.714*1 = 1.741 v.
Voltage decrease B is correct.
33.
In the given circuit, what is RUNK equal to if RV must be adjusted to
1,232
in order to balance the bridge?
a) 220
b) 6,899
c) 1,232
d) More information is needed in order to find RUNK
Answer: Option A
Explanation:
In order to balance the bridge.
560/(560+100) = 1232/(1232+R).
So R = 220 ohm
34.With 6 V applied, what is the voltage across R2 of a parallel
combination of R2 (1 k ), R3 (2 k ), and R4 (1 k ) in series with
R1, whose value is 2 k ?
a) 1 V
b) 3 V
c) 5 V
d) 6 V
Answer: Option A
Explanation:
Rtotal=2.57ohm
Itotal=v/r=6/2.57=2.33A
by voltage divider rule
voltage across R2=6*1/2+1+2+1=1V.
35.What is the power dissipated by R1, R2, and R3?
a) P1 = 0.13 W,
b) P1 = 0.26 W,
c) P1 = 0.52 W,
d) P1 = 1.04 W,
Answer: Option B
P2
P2
P2
P2
=
=
=
=
0.26
0.52
0.92
1.84
W,
W,
W,
W,
P3
P3
P3
P3
=
=
=
=
0.12
0.23
0.46
0.92
W
W
W
W
Explanation:
Find out total resistace i.e. 11/3kohm
Find out current i.e. 59/(11/3)mA= 16.09mA
Now by formula i2R find out power dissipated
True/False
1.
In the given circuit, the Thevenin voltage equals 6 V
True
False
Answer: Option A
Explanation:
Current flowing in loop 1 is,
-200I-600I-400I+12 = 0.
This implies, I=0.01A
Vth= 0.01A * 600 Ohms = 6V.
Hence the correct option is [A]
2.The voltage across R3 is 20 volts
True
False
Answer: Option B
We get current in mesh 3 & 2 are 11.11 & 16.66 amps respectively.
So difference we get as 5.55 & vol is 4*5.55 which is not 20 so false
3.The voltage across R1 is 175 volts
True
False
Answer: Option A
Because voltage in parallel remains same as that of input
4.
In the given circuit, the Thevenin resistance equals 800
True
False
Answer: Option B
.
Explanation:
When we short 12V we get (400+600) ohm resistance then 600 parallel with
600 gives 300 ohm finally we get 300+800 ohm i.e. 1100 ohm
5.The voltmeter will read 18 volts
True
False
Answer: Option A
Explanation:
Lets say point between R8 and R10 be A and point between R7 and R9 be B.
Now, R8, R10 in series so Rt1 = 2+3 = 5 ohm.
And R7, R9 in series so Rt2 = 1+4 = 5 ohm.
Rt=(Rt1Rt2)/(Rt1+Rt2) = 5/2 ohm.
Total current = V/Rt = (90*2)/5 = 36 amp.
Since Rt1 and Rt2 are equal therefore equal current will flow through each
branch = 36/2 = 18 amp.
Voltage drop across R8 = 18*2 = 36v.
Potential at point A = 90-36 = 54v.
Voltage drop across R7 = 18*1 = 18v.
Potential at point B = 90-18 = 72v.
Potential diff. between A and B gives voltmeter reading = 72-54 = 18v
6.Bleeder current is the total current left after the total divider
current is subtracted from the total current into the circuit
True
False
Answer: Option B
7.When analyzing series–parallel circuit currents, you should start
with the current in the branch farthest from the source
True
False
Answer: Option B
8.The power dissipated by R4 is 211 mW
True
False
Answer: Option A
Explination
Total Resistance = 1.8k ohm.
Than,I=185/1.8.
Then,
P = I^2*R.
211 mW.
9.The total resistance in the circuit is 1.6 k
True
False
Answer: Option A
10.The current through R1 is 17 mA.
True
False
Answer: Option A
.
11.If the output voltage of a certain loaded voltage divider is 12 V,
the output voltage might decrease when the load is removed.
True
False
Answer: Option B
12.If the Wheatstone bridge is balanced in the given circuit, the
voltage between points A and B (VAB) equals the source voltage
(VS)
True
False
Answer: Option B
13.The current through R6 is 8.5 mA
True
False
Answer: Option B
14.Observed voltages not being shared identify components in
parallel in a series–parallel circuit
True
False
Answer: Option B
15.R2 is open
True
False
Answer: Option B
16.The total power is 10 watts
True
False
Answer: Option B
17.
The total resistance in the given circuit can be found using the
formula:
RT = R1 + R2 || R3 || R4.
True
False
Answer: Option A
18.When a load resistance is connected to the output of a voltage
divider circuit, the source current increases
True
False
Answer: Option A
19.Opens and shorts are typical problems that occur in electric
circuits
True
False
Answer: Option A
20.A Wheatstone bridge may be used to determine the value of an
unknown resistance
True
False
Answer: Option A
21.The voltage out when a 10 k
load is connected is 5.7 volts
True
False
Answer: Option A
22.When resistors burn out, they usually short
True
False
Answer: Option B
23.Attaching a 6 k
load to a voltage divider will cause a smaller
decrease in the output voltage than will attaching a 5 k
load
True
False
Answer: Option A
24.A loaded voltage divider is a common application of a seriesparallel circuit
True
False
Answer: Option A
Fill in the blanks
1.The loading effect of a voltmeter can be ignored if ____
a) the measured voltage is very high
b) the measured voltage is very low
c) the meter's resistance is at least 10 times greater than the
resistance across which it is connected
d) the meter's resistance is at least 10 times less than the
resistance across which it is connected
Answer: Option C
2.A Thevenin equivalent circuit contains _____.
a) a voltage source in series with a resistance
b) a current source in series with a resistance
c) resistors in a series-parallel configuration
d) many voltage sources
Answer: Option A
3.
In the given circuit, the current flowing through R3 equals ______
a) 10 mA
b) 21.11 mA
c) 90 mA
d) 100 mA
Answer: Option A
4.Series components in a series–parallel circuit may be in series with
other _______________ components, or with other
_______________ components
a) individual, combinations of
b) series, parallel
c) parallel, series
d) shunt, parallel
Answer: Option A
5.If four 10 k resistors are in series with a single 20 k resistor
and one of the parallel resistors shorts, the voltage across the other
parallel resistors ________
a) Increases
b) decreases
c) remains the same
d) drops to zero
Answer: Option B
6.
In the given circuit, the voltage dropped across R1 equals _____
a) 1 V
b) 9 V
c) 10 V
d) 19 V
Answer: Option B
7.___ is often used to analyze multiple-source circuits
a) Thevenin's theorem
b) Superposition
c) Kirchhoff's law
d) Ohm's law
Answer: Option B
8.
If R3 opens in the given circuit, the total resistance (RT) between
points A and B equals ____.
a) 900
b) 100
c) 110
d) infinite resistance
Answer: Option C
9.If a Wheatstone bridge is balanced, its output voltage is ____
a) the same as its input voltage
b) very high
c) dependent on the unknown resistor value
d) equal to 0 V
Answer: Option D
10.When a load is connected to a voltage divider, the total resistance
of the circuit will ________
a) increase
b) decrease
c) remain the same
d) double
Answer: Option B
11.
In the given circuit, the total resistance (RT) between points A and B
equals _____.
a) 10
b) 100
c) 900
d) 1010
Answer: Option B
Explanation:
r2 and r3 are parallel. So r2*r3/r2+r3 = 90 ohm.
Then r1 and new resistance will be series. So 10 ohm + 90 ohm = 100 ohm.
12.
In the given circuit, the voltage at point A equals ______
a) –10 V
b) +1 V
c) +9 V
d) +10 V
Answer: Option D
13.
If the voltage between points A and B equals 9 V in the given circuit,
then VR3 equals ______.
a) 0.9 V
b) 8.1 V
c) 9 V
d) More information is needed to find VR3
Answer: Option B
Explanation:
Total resistance is 90(parallel)+10(both are in series) = 100.
From this total current is 9/100 = 0.09.
Voltage drop across 10 ohm is 10*0.09 = 0.9.
Voltage after 10 ohm is 9-0.9 = 8.1v