Unit 9- Electromagnets

What is created when an iron core is inserted into a coil and an electric current flows?

• Permanent magnet

• Electromagnet

• Compass

• Bar magnet

What is the core of an electromagnet made out of?

• plastic

• copper

• iron

• rock

What happens when the electric current flows through the coil?

• It repels iron

• It attracts iron

• It becomes hot

• It becomes lighter

What happens when the electromagnet is turned off?

• It changes poles

• It attracts iron

• It becomes hot

• It drops the iron

How can you know which part of the electromagnet is the North pole?

• The South needle of a compass points to it

• The North needle of a compass points to it

• The positive terminal of the battery is facing it

• The negative terminal of the battery is facing it

What happens to the poles of an electromagnet when the direction of the flowing current is reversed?

• The poles disappear

• The electromagnet loses its poles

• The north and south poles switch

• The poles remain the same

What does a galvanometer measure? (pick 2)

• speed of the current

• size of the current

• length of the current

• direction of the current

How can you strengthen an electromagnet's attraction to iron?

• Remove the iron core

• Decrease the size of the current

• Increase the number of coil loops

• Use a weaker battery

What happens to the strength of the electromagnet when the number of coil loops is increased?

• The strength remains the same

• The strength increases

• The strength decreases

• The electromagnet stops working

What is the relationship between the size of the current and the strength of the electromagnet?

• The strength is random

• The strength increases with current size

• The strength is not affected by current size

• The strength decreases with current size