Bar Magnets

Question 1

What is a magnetic field?

Answer 1

A region surrounding a magnetic object in which other magnetic objects will experience a force.

Question 2

Around every bar magnet is what?

Answer 2

A magnetic field

Question 3

What are the two poles of a bar magnet called?

Answer 3

North and south

Question 4

What can the shape of a magnetic field be shown by?

Answer 4

Field lines

Question 5

What are the two important rules of field lines?

Answer 5

They must:

1. Never cross or touch
2. Point away from the north and towards the south.

Question 6

How can you tell how strong a magnetic field is?

Answer 6

The closer the field lines, the stronger the magnetic field

Question 7

Why are bar magnets called permanent magnets?

Answer 7

Their magnetism cannot be switched on or off.

Question 8

What are bar magnets usually made of?

Answer 8

Steel

Question 9

What is a plotting compass?

Answer 9

A small, suspended magnet enclosed in an aluminium case with a glass window.

Question 10

What does a plotting compass do?

Answer 10

It comes to rest pointing along a magnetic field line.

Question 11

Explain how you can plot field lines around a bar magnet in a series of steps. [6]

Answer 11

1. Place the plotting compass on a sheet of white paper and draw its outline.
2. Place the compass near the north pole and draw a dot, using a pencil, where the needle is pointing.
3. Move the compass so that the dot is directly below the tail of the compass.
4. Mark a new dot where the head is pointing.
5. Continue this process until you reach the magnet again and draw the field line.
6. Repeat several times until several field lines are drawn.