Electric Circuits Mcqs

Q:

If the current flowing through an inductor of inductance 0.3Henry is 5.3t²+4.7t. Calculate the power.

A) 0 B) 1
C) 16.854t³+22.41t²+6.62t D) 15.3t³+27.8t²+19
 
Answer & Explanation Answer: C) 16.854t³+22.41t²+6.62t

Explanation: P= L*i*(di/dt).

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Q:

The insulating medium between the two plates of capacitor is known as __________

A) Electrode B) Capacitive medium
C) Conducting medium D) Dielectric
 
Answer & Explanation Answer: D) Dielectric

Explanation: The conducting surfaces are called electrodes and the insulating medium is called Dielectric.

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19
Q:

An Inductor works as a ___________ circuit for DC supply.

A) Open B) Short
C) Polar D) Non-polar
 
Answer & Explanation Answer: B) Short

Explanation: Induced voltage across an inductor is zero if the current flowing through it is constant. I.e. Inductor works as a short circuit for DC supply.

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13
Q:

If the voltage across a capacitor is constant, then current passing through it is ________

A) 1 B) 0
C) -1 D) Infinity
 
Answer & Explanation Answer: B) 0

Explanation: I= c*(dv/dt).

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13
Q:

If a capacitor of capacitance 9.2F has a voltage of 22.5V across it. Calculate the energy of the capacitor.

A) 5062.5W B) 506.25W
C) 50.625W D) 50625W
 
Answer & Explanation Answer: B) 506.25W

Explanation: E= ½ cv².

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11
Q:

The units for inductance is _________ and capacitance is ___________

A) Faraday, Henry B) Coulomb, Faraday
C) Henry, Faraday D) Henry, Coulomb
 
Answer & Explanation Answer: C) Henry, Faraday

Explanation: The unit for inductance is ‘Henry’ and capacitance is ‘Faraday’.

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12
Q:

The expression for energy of an inductor ____________

A) ½ LI B) L/2I
C) ½ L²I D) ½ LI²
 
Answer & Explanation Answer: D) ½ LI²

Explanation: E=∫p dt
=∫ LI*(dI/dt).dt
= L∫I dI
= ½ LI².

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13
Q:

The Inductor doesn’t allow sudden changes in ___________

A) Voltage B) Current
C) Resistance D) Inductance
 
Answer & Explanation Answer: B) Current

Explanation: Any small change in current occurs within zero time across the gives an infinite voltage which is practically impossible. So, in a fixed inductor, the voltage cannot change abruptly.

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