Look at the figure and answer the following questions:

(i) The end P becomes:

1. south pole
2. north pole
3. cannot say
4. none of the above

(ii) The end Q becomes:

1. south pole
2. north pole
3. cannot say
4. none of the above

(iii) The given bar shows magnetic properties only when …………… through the solenoid and it loses the magnetic properties as soon as the ……………

1. current is switched off, current is switched on
2. current is switched on, current is switched off
3. current is switched on, current is switched on
4. both (a) and (b)

(i) south pole

(ii) north pole

(iii) current is switched on, current is switched off

Reason —

(i) When current is passed through the winding of the solenoid by closing the key K, the end P of the bar becomes the south pole, since current at this face is clockwise.

(ii) When current is passed through the winding of the solenoid by closing the key K, the end Q of the bar becomes the north pole, since current at this face is anticlockwise.

(iii) The bar shows magnetic properties only when an electric current flows through the solenoid and it loses the magnetic properties as soon as the current is switched off (since soft iron has low retentivity), thus it is a temporary magnet.