Physics

Question 1

1Faraday's law states that the induced e.m.f. is proportional to

Medium

A. the mass of the magnet B. the resistance of the coil C. the temperature D. the rate of change of magnetic flux linkage

Question 2

2Lenz's law states that the induced current flows in a direction that

Medium

A. opposes the change producing it B. is always clockwise C. helps the change producing it D. is random

Question 3

3Faraday's law states that the induced e.m.f. is proportional to the

Easy

A. resistance B. current only C. rate of change of magnetic flux D. mass of the coil

Question 4

4Eddy currents in a transformer core are reduced by

Medium

A. removing the core B. making the core from thin insulated laminations C. using a solid copper core D. increasing the current

Question 5

5A generator converts

Easy

A. mechanical energy to electrical energy B. heat to light C. light to electrical energy D. electrical to mechanical energy

Question 6

6An a.c. generator changes

Easy

A. electrical energy into mechanical energy B. chemical energy into electrical energy C. mechanical energy into electrical energy D. heat into light

Question 7

7A straight conductor 0.5 m long moves at 4 m/s perpendicular to a 0.2 T field. The induced e.m.f. is

Hard

A. 1.6 V B. 0.04 V C. 4 V D. 0.4 V

Question 8

8Lenz's law states that the induced current

Easy

A. aids the change B. is always zero C. flows clockwise only D. opposes the change producing it

Question 9

9The induced e.m.f. in a coil increases if

Easy

A. the magnet is held still B. the coil is removed C. resistance increases D. the number of turns increases

Question 10

10A coil of 200 turns has its flux changed from 0.05 Wb to 0 in 0.1 s. The average induced e.m.f. is

Hard

A. 0.1 V B. 1 V C. 10 V D. 100 V