Non-Inductive DC Circuit MCQ [Free PDF] - Objective Question Answer for Non-Inductive DC Circuit Quiz

11. 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

Answer: A

The average emf induced is proportional to the current per unit time, the constant of proportionality being L.

Hence emf = LI/t. Making L the subject of the formula, we get

L = emf × t/I.

12. Among the following, which is the right formula for the inductance of N turns?

A. L = et/Ni
B. L = N × i × e × t
C. L = Ni/et
D. L = N/iet

Answer: A

We know that:

emf = NLi/t

Inductance = L = et/N.

13. For a coil having a magnetic circuit of constant reluctance, the flux is ___________ to the current.

A. Directly proportional
B. Inversely proportional
C. Not related
D. Very large compared to

Answer: A

For a coil having a magnetic circuit of constant reluctance, the flux is directly proportional to the current.

14. For a coil having a magnetic circuit of constant reluctance, if the flux increases, what happens to the current?

A. Increases
B. Decreases
C. Remains constant
D. Becomes zero

Answer: A

For a coil having a magnetic circuit of constant reluctance, the flux is directly proportional to the current. Hence as the flux increases, the current also increases.

15. The unit for inductance is ___________

A. Ohm
B. Henry
C. A/m
D. A/s

Answer: B

The unit of induction is named after a famous scientist Joseph Henry who independently discovered electromagnetic induction.

16. If either the inductance or the rate of change of current is doubled, the induced e.m.f?

A. Remains constant
B. Becomes zero
C. Doubles
D. Becomes half

Answer: C

If either the inductance or the rate of change of current is doubled, the induced e.m.f. becomes double because of emf = LI/t.

17. If the current changes from 5A to 3A in 2 seconds and the inductance is 10H, calculate the emf.

A. 5V
B. 10V
C. 15V
D. 20V

Answer: B

We know that:

emf = L(i2 − i1)/t

Substituting the values from the question, we get emf = 10V.

18. If the current changes from 5A to 3A in x sec and inductance is 10H. The emf is 10V, calculate the value of x.

A. 2s
B. 3s
C. 4s
D. 5s

Answer: A

We know that:

emf = L(i2 − i1)/t

Substituting the values from the question, we get x = 2s.

19. If the current changes from 3A to 5A in 2s and the emf is 10V. Calculate the inductance.

A. 10H
B. 20H
C. 30H
D. 40H

Answer: A

If the current changes from 5A to 3A in 2s and the emf is 10V. Calculate the inductance.

20. As the number of turns in the coil increases, what happens to the inductance of the coil?

A. Increases
B. Decreases
C. Remains the same
D. Becomes zero

Answer: A

Inductance is directly proportional to the square of the number of turns in the coil, hence as the number of turns increases, inductance also increases.

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