Electrical Engineering Mcqs

Inductor does not allow the sudden change of

A. current
B. voltage
C. power
D. None of the above

Voltage developed across an inductor is expressed bY
Sudden change of current means di will change at dt → 0 (dt tends to zero), so sudden change of current means infinite voltage. Therefore it is not possible.

Power dissipation in ideal inductor is

A. Maximum
B. Minimum
C. Zero
D. A finite value

Internal resistance of ideal inductor is zero. As there is no resistance, there should not be any dissipation of power. Pure inductor has no resistive component, so it active power dissipation is zero.

Which of the following are the passive elements?

A. Resistor
B. Bulb
C. Both
D. None of these.

When the element is not capable of delivering energy independently, are called as passive element. Both resistor and bulb are the passive elements and they can’t increase the energy level of a circuit

If 1 A current flows in a circuit, the number of electrons flowing through this circuit is

A. 0.625 × 1019
B. 1.6 × 1019
C. 1.6 × 10-19
D. 0.625 × 10-19

The charge of one electron is 1.6 × 10 – 19 coulomb. Again 1 A current means transferring of 1 coulomb charge per one second.

The resistivity of the conductor depends on

A. area of the conductor.
B. length of the conductor.
C. type of material.
D. none of these.

The resistivity is a property of material, defined as the resistance between two opposite faces of a cube of a material of unit volume. That is why resistivity is only the unique property of material and it does not depend upon the dimension of any piece of material.

The resistance of a conductor of diameter d and length l is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be

A. R Ω
B. 2R Ω
C. 4R Ω
D. 8R Ω

As per law of resistance, the resistance of the conductor is inversely proportional to its cross-sectional area i.e. it is inversely proportional to the square of the diameter of cross-sectional area of the conductor. As per same law of resistance, the resistance of the conductor is directly proportional to the length of the conductor.

How many coulombs of charge flow through a circuit carrying a current of 10 A in 1 minute?

A. 10
B. 60
C. 600
D. 1200

1 Ampere current means flowing of 1 Coulomb charge per second. That means 10 A current in 1 minute or 60 seconds implies 10 × 60 = 600 coulombs.

The unit of resistivity is

A. Ω.
B. Ω – metre.
C. Ω / metre.
D. Ω / m².

Instantaneous power in inductor is proportional to the

A. product of the instantaneous current and rate of change of current.
B. square of instantaneous current.
C. square of the rate of change of current.
D Temperature of the inductor.

The instantaneous voltage across the inductor is expressed as the product of inductance and rate of change of current through it. Power is expressed as the product of current and voltage. Hence instantaneous power in an inductor is proportional to the product of instantaneous current and rate of change of current through it.

The voltage induced in an inductor is represented as,

A. product of its inductance and current through it.
B. ratio of its inductance to the current through it.
C. ratio of the current through it to its inductance.
D. product of its inductance and rate of change of current through it.

The instantaneous voltage across the inductor is expressed as the product of inductance and a rate of change of current through it as it doesn’t allow any certain change of current through it. Voltage induced in an inductor is written as