Quick review

Which statement about a magnet is correct?

• A A magnet attracts a gold rod.

• B A magnet does not attract a plastic rod.

• C A magnet never repels another magnet.

• D A magnet sometimes repels an unmagnetised nickel rod

• A

• B

• C

• D

A student wishes to make a permanent magnet. She has an iron rod and a steel rod. Which rod should she use to make the permanent magnet, and is this rod a hard magnetic material or a soft magnetic material?

• A

• B

• C

• D

Which statement about magnetism is correct?

• An unmagnetised iron bar becomes magnetised when it is placed near a magnet.

• An unmagnetised steel bar can be magnetised by passing a current through it

• The direction of magnetic field lines is from an S-pole to an N-pole.

• The N-poles of two magnets attract each other.

In which pair are both materials magnetic

• aluminium and copper

• copper and iron

• iron and steel

• steel and aluminium

Which group contains only non-ferrous metals?

• aluminium, brass, iron

• brass, copper, lead

• copper, iron, steel

• copper, lead, steel

An electromagnet with a soft-iron core is connected to a battery and an open switch. The soft-iron core is just above some small soft-iron nails.

The switch is now closed, left closed for a few seconds, and then opened. What do the soft-iron nails do as the switch is closed, and what do they do when the switch is then opened?

• A

• B

• C

• D

Which action will demagnetise a magnetised piece of steel?

• Cool it in a freezer for several hours.

• Hit it repeatedly with a hammer.

• Put it in a coil carrying a direct current (d.c.).

• Put it near an unmagnetised piece of iron.

Which statement about a permanent bar magnet is correct?

• It is made from a soft magnetic material.

• It repels a non-magnetic material.

• Its field lines cross each other where the magnetic field is strong.

• Its N-pole repels the N-pole of another magnet.

Which test could be used to find which end of a magnet is the north pole?

• putting it near a compass needle

• putting it near a ferrous metal

• putting it near a non-ferrous metal

• putting it near a steel spoon