200+ Capacitance and Capacitor MCQ – Objective Question Answer for Capacitance and Capacitor Quiz

61. Capacitor is a device used to __________

A. store electrical energy
B. vary the resistance
C. store magnetic energy
D. dissipate energy

Answer: A

The capacitor is used to store the charge. It stores electrical energy between the plates.

 

62. Capacitor stores which type of energy?

A. kinetic energy
B. vibrational energy
C. potential energy
D. heat energy

Answer: C

Capacitor store charge in between the plates. This charge is stationary so we can say capacitors store potential energy.

 

63. Capacitor blocks__________ after long time.

A. alternating current
B. direct current
C. both alternating and direct current
D. neither alternating nor direct current

Answer: B

The capacitor blocks direct current at steady-state and passes alternating current.

The capacitor blocks DC because there is no electrical connection between the 2 electrodes; rather there is a vacuum or an insulator.

 

64. Why does the capacitor block the dc signal at a steady state?

A. due to the high frequency of the dc signal
B. due to zero frequency of dc signal
C. capacitor does not pass any current at a steady-state
D. due to zero frequency of dc signal

Answer: D

The frequency of the dc signal is zero. So, Capacitive reactance XC = 1/2πfc becomes infinite and the capacitor behaves as an open circuit for dc signal. Hence, the capacitor blocks the dc signal.

The capacitor blocks DC because there is no electrical connection between the 2 electrodes; rather there is a vacuum or an insulator.

 

65. If a parallel plate capacitor of plate area 2m2 and plate separation 1m stores the charge of 1.77 × 10-11 C. What is the voltage across the capacitor?

A. 1 V
B. 2 V
C. 3 V
D. 4 V

Answer: A

The capacitance of a parallel plate capacitor is given as

C = €0A/d

On substituting values of d, and A, we get

C = 2€0.
Q = CV
V = 1 V.

 

66. Which of the following is a passive device?

A. Transistor
B. Rectifier
C. Capacitor
D. Vacuum Tubes

Answer: C

The capacitor is a passive device as it consumes power rest all generate power so, they are active devices.

 

67. What is the value of capacitance of a capacitor that has a voltage of 4V and has 16C of charge?

A. 2F
B. 4F
C. 6F
D. 8F

Answer: B

In a capacitor, Q is directly proportional to V.

The constant of proportionality, in this case, is C, that is, the capacitance.

Hence Q = CV.

From the relation, C = Q/V = 16/4 = 4F.

 

68. For which medium capacitance is high?

A. Air
B. Mica
C. Water
D. Metal

Answer: D

Metals are assumed to have a high value of dielectric constant so they have high capacitance.

 

69. The conventional direction of electric field is ________

A. Positive to negative
B. Negative to positive
C. No specific direction
D. Direction cannot be determined

Answer: A

The conventional direction of field lines is from positive to negative. The field lines originate at the positive charge and terminate at the negative charge.

 

70. Electric field originates at __________

A. Positive charge
B. Negative charge
C. Neither positive nor negative
D. Both positive and negative

Answer: A

The electric field originates at the positive charge and terminates at the negative charge. The conventional direction of the field is from positive to negative.

Scroll to Top