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

Assume that two of the electrons at the negative terminal have attached themselves to a nearby neutral atom. there is now a negative ion with a charge -2e at this terminal. what are the electric potential and electric potential energy of the negative ion relative to the electron? the electric potential and the electric potential energy are both twice as much. the electric potential is twice as much and the electric potential energy is the same. the electric potential is the same and the electric potential energy is twice as much. the electric potential and the electric potential energy are both the same. the electric potential is the same and the electric potential energy is increased by the mass ratio of the oxygen ion to the electron. the electric potential is twice as much and the electric potential energy is increased by the mass ratio of the oxygen ion to the electron.