# Multiple choice question for engineering

## Set 1

1. The charging time constant of a circuit consisting of a capacitor is the time taken for the charge in the capacitor to become __________% of the initial charge.

a) 33

b) 63

c) 37

d) 36

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^{-t}/RC). When RC=t, we have: Q=Q0(1-e

^{-1})= 0.63*Q0. Hence the time constant is the time taken for the charge in a capacitive circuit to become 0.63 times its initial charge.

2. The discharging time constant of a circuit consisting of a capacitor is the time taken for the charge in the capacitor to become __________% of the initial charge.

a) 33

b) 63

c) 37

d) 36

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^{-t}/RC). When RC=t, we have: Q=Q0(e

^{-1})= 0.37*Q0. Hence the time constant is the time taken for the charge in a capacitive circuit to become 0.37 times its initial charge.

3. A circuit has a resistance of 2 ohm connected in series with a capacitance of 6F. Calculate the charging time constant.

a) 3

b) 1

c) 12

d) 8

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4. A circuit has a resistance of 5 ohm connected in series with a capacitance of 10F. Calculate the discharging time constant.

a) 15

b) 50

c) 5

d) 10

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5. What is the value of current in a discharging capacitive circuit if the initial current is 2A at time t=RC.

a) 0.74A

b) 1.26A

c) 3.67A

d) 2.89A

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6. What is the value of current in a charging capacitive circuit if the initial current is 2A at time t=RC.

a) 0.74A

b) 1.26A

c) 3.67A

d) 2.89A

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7. While discharging, what happens to the current in the capacitive circuit?

a) Decreases linearly

b) Increases linearly

c) Decreases exponentially

d) Increases exponentially

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^{-t}/RC. From this equation, we can see that the current is exponentially decreasing since e is raised to a negative power.

8. While discharging, what happens to the voltage in the capacitive circuit?

a) Decreases linearly

b) Increases linearly

c) Decreases exponentially

d) Increases exponentially

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^{-t}/RC. From this equation, we can see that the voltage is exponentially decreasing since e is raised to a negative power.

9. While charging, what happens to the current in the capacitive circuit?

a) Decreases linearly

b) Increases linearly

c) Decreases exponentially

d) Increases exponentially

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^{-t}/RC). From this equation, we can see that the current is exponentially increasing since e is raised to a negative power and we are subtracting it from 1. Hence as the value of e

^{-t}/RC in-creases, the current increases exponentially.

10. While charging, what happens to the voltage in the capacitive circuit?

a) Decreases linearly

b) Increases linearly

c) Decreases exponentially

d) Increases exponentially

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^{-t}/RC). From this equation, we can see that the voltage is exponentially increasing since e is raised to a negative power and we are subtracting it from 1. Hence as the value of e

^{-t}/RC in-creases, the voltage increases exponentially.

## Set 2

1. In case of Inductive circuit, Frequency is ______________ to the current.

a) Directly proportional

b) Inversely proportional

c) Unrelated

d) Much greater than

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2. In a pure inductive circuit, the power factor is?

a) Maximum

b) Minimum

c) 0

d) Infinity

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3. What happens to the inductance when the current in the coil becomes double its original value?

a) Becomes half

b) Becomes four times

c) Becomes infinity

d) Becomes double

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4. Among the following, which is the right formula for inductance?

a) L=emf*t/I

b) L=emf/t*I

c) L=emf*I/t

d) L=emf*t*I

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5. Among the following, which is the right formula for growth in an inductive circuit?

a) VL=V(1-e^{-t}/time constant)

b) VL=V(1-e^{t} /time constant)

c) VL=(1-e^{-t} /time constant)

d) VL=V(e^{-t} /time constant)

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^{-t}/time constant). As the time increases, the current in the inductor increases hence the voltage also increases.

6. The charging time constant of a circuit consisting of an inductor is the time taken for the voltage in the inductor to become __________% of the initial voltage.

a) 33

b) 63

c) 37

d) 36

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^{-t}/time constant). When time constant=t, we have: V=V0(1-e

^{-1})= 0.63*V0. Hence the time constant is the time taken for the charge in an inductive circuit to become 0.63 times its initial charge.

7. What is the time constant of an inductive circuit?

a) LR

b) R/L

c) 1/LR

d) L/R

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8. Calculate the time constant of an inductive circuit having resistance 5 ohm and inductance 10H.

a) 2s

b) 4s

c) 5s

d)10s

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9. Calculate the resistance in an inductive circuit whose time constant is 2s-1 and the inductance is 10H.

a) 7ohm

b) 10ohm

c) 2ohm

d) 5ohm

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10. Calculate the inductance in an inductive circuit whose time constant is 2s-1 and the resistance is 5 ohm.

a) 10H

b) 20H

c) 5H

d) 15H

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## Set 3

1. In case of Inductive circuit, Frequency is ______________ to the inductance.

a) Directly proportional

b) Inversely proportional

c) Unrelated

d) Much greater than

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2. In case of Inductive circuit, Frequency is ______________ to the current.

a) Directly proportional

b) Inversely proportional

c) Unrelated

d) Much greater than

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3. In an inductive circuit, when the XL value increases, the circuit power factor?

a) Increases

b) Decreases

c) Remains the same

d) Becomes zero

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4. If the current and voltage are 90 degree out of phase, the power factor will be?

a) 0

b) Infinity

c) 1

d) Insufficient information provided

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5. In a pure inductive circuit, the power factor is __________

a) Maximum

b) Minimum

c) 0

d) Infinity

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6. If the power factor is 10 and the value of inductive reactance is 20 ohm, calculate the resistance in the circuit.

a) 1 ohm

b) 2 ohm

c) 3 ohm

d) 4 ohm

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7. If the resistance in a circuit is 2 ohm and the inductive resistance is 20 ohm, calculate the power factor.

a) 10

b) 20

c) 30

d) 40

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8. If the power factor is 10 and the resistance is 2 ohm, calculate the inductive reactance.

a) 10 ohm

b) 20 ohm

c) 30 ohm

d) 40 ohm

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9. What is the unit for inductive reactance?

a) Henry

b) Ohm

c) Farad

d) Volts

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10. An induced emf is said to be ________

a) Inductive

b) Capacitive

c) Resistive

d) Cannot be determined

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## Set 4

1. Find the value of v if v1=20V.

a) 10V

b) 12V

c) 14V

d) 16V

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2. Calculate the current A.

a) 5A

b) 10A

c) 15A

d) 20A

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3. Calculate the current across the 20 ohm resistor.

a) 20A

b) 1A

c) 0.67A

d) 0.33A

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4. Calculate the value of I3, if I1= 2A and I2=3A.

a) -5A

b) 5A

c) 1A

d) -1A

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5. Find the value of i2, i4 and i5 if i1=3A, i3=1A and i6=1A.

a) 2,-1,2

b) 4,-2,4

c) 2,1,2

d) 4,2,4

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6. What is the value of current if a 50C charge flows in a conductor over a period of 5 seconds?

a) 5A

b) 10A

c) 15A

d) 20A

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7. KCL deals with the conservation of?

a) Momentum

b) Mass

c) Potential Energy

d) Charge

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8. KCL is applied at _________

a) Loop

b) Node

c) Both loop and node

d) Neither loop nor node

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9. KCL can be applied for __________

a) Planar networks

b) Non-planar networks

c) Both planar and non-planar

d) Neither planar nor non-planar

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10. What is the value of the current I?

a) 8A

b) 7A

c) 6A

d) 5A

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## Set 5

1. Mesh analysis is generally used to determine?

a) Voltage

b) Current

c) Resistance

d) Power

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2. KVL is associated with____________

a) Mesh analysis

b) Nodal analysis

c) Both mesh and nodal

d) Neither mesh nor nodal

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3. KCL is associated with_________

a) Mesh analysis

b) Nodal analysis

c) Both mesh and nodal

d) Neither mesh nor nodal

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4. Nodal analysis is generally used to determine?

a) Voltage

b) Current

c) Resistance

d) Power

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5. Find the value of the source current from the following circuit.

a) 2.54A

b) 6.67A

c) 3.35A

d) 7.65A

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_{3}=(3+j0)A V

_{2}=I

_{3}R=(3+j0)(8+j0)=(24+j0)V I2=V2/Xc=(j1.5) A I1 =I2 +I3 =(0+j1.5)+(3+j0)=(3+j1.5)A I1=(3

^{2}+1.5

^{2})

^{1/2}= 3.35A.

6. Find the value of the source voltage from the following circuit.

a) 49.2V

b) 34.6V

c) 65.2V

d) 25.6V

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^{2}+1.5

^{2})

^{1/2}= 3.35A. V1 =I1(R+jXL) =(15+j30)V E=V1 +V2 =(39+j30)V E=(39

^{2}+30

^{2})

^{1/2}= 49.2V.

7. According to KVL, the algebraic sums of all the IR products and the voltages in a loop is?

a) Always positive

b) Always negative

c) Always zero

d) Always infinity

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8. Kirchhoff’s laws are valid for ___________

a) Linear circuits only

b) Both linear and non-linear circuits

c) Neither linear nor non-linear circuits

d) Both linear and non-linear circuits

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9. KCL is based on _____________

a) Law of conservation of energy

b) Law of conservation of charge

c) Both conservation of energy and charge

d) Neither conservation of energy nor charge

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10. KVL is based on ___________

a) Law of conservation of energy

b) Law of conservation of charge

c) Both conservation of energy and charge

d) Neither conservation of energy nor charge