Explore topic-wise MCQs in Physics.

This section includes 6 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.

1.

A metal rod is forced to move with constant velocity along two parallel metal rails, connected with a strip of metal at one end across a magnetic field (B) of 0.5 T, pointing out of the page. The rod is of length 45 cm and the speed of the rod is 70 cm/s. The rod has a resistance of 10 Ω and the resistance of the rails and connector is negligible. What is the rate at which energy is being transferred to thermal energy?

A. 0.225 W
B. 22.55 W
C. 2.25 × 10-4 W
D. 2.25 × 10-3 W
Answer» E.
Discussion
2.

A bar of length 2m is said to fall freely in a magnetic field of magnitude 50 T. What is the motional emf in the bar when it has fallen 40 meters?

A. 700 V
B. 2100 V
C. 2800 V
D. 1400 V
Answer» D. 1400 V
Discussion
3.

Induced emf and motional emf are exactly the same.

A. True
B. False
Answer» C.
Discussion
4.

A bar of length 0.15 m slides along metal rails at a speed of 5 m/s. The bar and rails are in a magnetic field of 40 T, pointing out into the page. The resistance of two resistors in parallel is both 20 Ω, and the resistance of the bar is 5 Ω. What is the current in the bar?

A. 1 A
B. 2 A
C. 3 A
D. 5 A
Answer» C. 3 A
Discussion
5.

A bar of length 0.7 m slides along metal rails at a speed of 1 m/s. The bar and rails are in a magnetic field of 20 T, pointing out into the page. Calculate the motional emf.

A. 0.7 V
B. 7 V
C. 14 V
D. 1.4 V
Answer» D. 1.4 V
Discussion
6.

Identify the expression for the motional electromotive force from the following?

A. E = -vLB
B. E = vLB
C. E = \(\frac {v}{LB}\)
D. E = \(\frac {LB}{v}\)
Answer» B. E = vLB
Discussion