Question

In which of the following devices temporary magnets are used?

• A. Dynamo
• B. Electric motors
• C. Generators
• D. Electric cranes

Answer 1

The correct option is D

Electric cranes

1. In electromagnets, once the current stops flowing, it loses its magnetic effect.
2. Electromagnets are used widely in electric bells, electric cranes, tape recorders, speakers, etc.
3. Thus, temporary magnets are used in electric cranes.
4. Permanent magnets are used in dynamos, electric motors, generators, electron accelerators, door locks, etc.

Hence, option (D) is correct.