Figure shows a coil wound around a soft iron bar XY. (a) State the polarity at the end X and Y as the switch is pressed. (b) Suggest one way of increasing the strength of the electromagnet so formed.

(a) The polarity at X — south pole and at Y — north pole.

(b) The strength of the electromagnet so formed can be increased by increasing the current in the coil.

Reason — The direction of current through the coil is marked in the figure below. From the figure, the current at end Y is in anticlockwise direction. Hence, end Y behaves as North pole. The current at end X is in clockwise direction. Hence, end X behaves as South pole.