electromagnets.

Question 1

what can the strength of a magentic field produced by a solenoid be increased by?

Answer 1

• using large current.
• using more turns of wire.
• placing turns closer together.
• putting a (soft) iron core into the middle of the solenoid.

Question 2

electric bell: what happens to the electromagnet when the switch is closed?

Answer 2

current flows.
magnetises the electromagnet.

Question 3

electric bell: what happens to the armature just after the switch is closed?

Answer 3

attracted to the electromagnet.

Question 4

electric bell: why does the armature move back after hitting the gong?

Answer 4

the cotacts a open so current no longer flows so no magnetic field.
spring pushes back to the original position.