P2.1.7 - Electromagnets

Question 1

How can you make an electromagnet using an iron core, wire, battery to separate a pile of paperclips and bits of paper.

Answer 1

1. Wrap the wire around an iron nail.
2. Connect it to the battery.
3. Iron paperclips will be attracted to the electromagnet, paper will not.
4. Move the electromagnet over the pile of paperclips and paper
5. Move the electromagnet away and turn off the battery to allow the paperclips to drop.
6. Repeat until all the iron has been removed leaving a pile of copper.

Question 2

How can you make an electromagnet stronger?

Answer 2

Add more loops of copper wire around the core.

Increase the current going through the coil of wire.

Use a magnetic metal as the electromagnet core (Iron, Nickel, Cobalt)

Question 3

How do you turn an electromagnet on and off?

Answer 3

Switch the electric current on or off.

Question 4

For an electromagnet to have a magnetic field a _______ must be flowing through the coil of wire around the core.

Answer 4

current

Question 5

Electromagnets usually have a magnetic material in the centre of a coil of wire called a…

Answer 5

core

Question 6

Most electromagnet cores are made from…

Answer 6

iron

Question 7

What is the pro and con of using iron as an electromagnet core?

Answer 7

Pro: It is easy to magnetise.

Con: It loses its magnetism easy.

Question 8

What is the pro and con of using a steel core in an electromagnet?

Answer 8

Pro: it keeps its magnetism even after you switch off the electromagnet.

Con: it is difficult to magnetise

Question 9

Compare permanent magnets and electromagnets.

Answer 9

You can turn an electromagnet on and off.

You can make electromagnets that are much stronger than permanent magnets.