1.) Which of these are needed to produce an electromagnet?

A. Electricity and sound
B. Electricity and magnetism
C. Light and heat
D. Sound and heat

2.) What is needed to increase the strength of an electromagnet

A. increase the size of the iron core.
B. increase the number of turns in the coil.
C. increase cthe amount of electricity in the circuit.
D. increase the amount of electricity in the magnet.

3.) why is electromagnet preferred to use than a permanent magnet

A. electro magnet produce electricity
B. permanent magnet are not strong.
C. the strength of electromagnets can be changed.
D. the strength of electromagnet is fixed.

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