Alternating EMF Generation MCQ [Free PDF] – Objective Question Answer for Alternating EMF Generation Quiz

1. Which, among the following, is the correct expression for alternating emf generated?

A. e = 2Blvsin(θ)
B. e = 2B2lvsin(θ)
C. e = Blvsin(θ)
D. e = 4Blvsin(θ)

Answer: C

The correct expression for alternating emf generated is e = Blvsin(θ). Where B stands for magnetic field density, l is the length of each of the parallel sides v is the velocity with which the conductor is moved and θ is the angle between the velocity and the length.

 

2. What should theta be in order to get maximum emf?

A. 00
B. 900
C. 1800
D. 450

Answer: B

The value of θ should be 900 in order to get maximum emf because e = Blvsin(θ) and sin is maximum when θ is 900.

 

3. Calculate the maximum emf when the velocity is 10m/s, the length is 3m and the magnetic field density is 5T.

A. 150V
B. 100V
C. 300V
D. 0V

Answer: A

We know that: emax = Bvl

Substituting the values from the given question, we get e = 150V.

 

4. When a coil is rotated in a magnetic field, the emf induced in it?

A. Is maximum
B. Is minimum
C. Continuously varies
D. Remains constant

Answer: C

When a coil is rotated in a magnetic field, the cross−sectional area varies due to which the number of flux lines crossing it varies, which causes the emf to vary continuously.

 

5. emf is zero if the angle between velocity and length is _____

A. 00
B. 900
C. 2700
D. 450

Answer: A

If the angle between velocity and length is zero, sinθ = 0

So, e = Bvlsinθ = 0.

 

6. In an A.C. generator, increase in the number of turns in the coil _________

A. Increases emf
B. Decreases emf
C. Makes the emf zero
D. Maintains the emf at a constant value

Answer: A

In an A.C. generator, the emf increases as the number of turns in the coil increases because the emf is directly proportional to the number of turns.

 

7. The number of cycles that occur in one second is termed as ___________

A. Waveform
B. Frequency
C. Amplitude
D. Period

Answer: B

The number of cycles that occur in one second is known as frequency. It is the reciprocal of the time period.

 

8. The variation of a quantity such as voltage or current shown on a graph is known as ___________

A. Waveform
B. Peak value
C. Instantaneous value
D. Period

Answer: A

The variation of a quantity, which is voltage or current in this case, shown on a graph with the x−axis as time is known as a waveform.

 

9. What is the duration of one cycle known as _________

A. Waveform
B. Peak value
C. Instantaneous value
D. Period

Answer: D

The duration of one cycle is known as a period. A function that repeats the same waveform at equal intervals of time is known as a periodic function.

 

10. The repetition of a variable quantity, recurring at equal intervals, is known as ___________

A. Waveform
B. Instantaneous value
C. Cycle
D. Period

Answer: C

Each repetition of a variable quantity, recurring at equal intervals, is termed a cycle.

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