SIMPLE PHENOMENON OF MAGNETISM

Which statement about a magnet is correct?

• A magnet attracts a gold rod.

• A magnet does not attract a plastic rod.

• A magnet never repels another magnet.

• A magnet sometimes repels an unmagnetised nickel rod.

Two nickel bars are placed close to the N-pole of a bar magnet. The nickel bars become magnetised.

• 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

• 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

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.

The ends of three metal rods are tested by holding end Q of rod 1 close to the others in turn.

The results are as follows.

End Q: attracts end R,

attracts end S,

attracts end T,

repels end U.

Which of the metal rods is a magnet?

• rod 1 only

• rod 1 and rod 2

• rod 1 and rod 3

• rod 3 only

How can a permanent magnet be demagnetised?

• cool the magnet for a long time

• hit the magnet repeatedly with a hammer

• leave the magnet in a coil which is connected to a battery

• shine bright light onto the magnet