1. Which of the following statements is / are correct about magnetic induction? I. It results in mutual attraction between the bodies concerned.

II. Adjacent parts of the bodies involved have OPPOSITE polarity.

III. When in use, keepers for storing magnets are magnetised by induction.

a
I , II and III
b
I only
c
I and III only
d
I and II only
2. What is the purpose of a magnetic relay?

a
To use a small current to switch on a larger current
b
To use a large current to switch on a small current
c
To change a small voltage into a larger voltage
d
To change a large voltage into a smaller voltage
3. The diagram shows the apparatus that can be used to make a magnet.

Which metal and which power supply are used to make a permanent magnet?

a
Steel and a 6v d. c. supply
b
Iron and a 6v a. c. supply
c
Iron and a 6v d. c. supply
d
Steel and a 6v a. c. supply