Question

1. The figure alongside shows an electromagnet. What is the polarity at the end of X?
2. Suggest a way by which the strength of the electromagnet referred to can be measured.

Answer 1

1. At end X, the current in the coil is clockwise when seen from that end. Therefore, by the clock rule, end X behaves as the south pole.
2. The strength of the electromagnet can be measured by bringing it near iron pins and counting the number of pins it attracts; a stronger electromagnet attracts more pins. Its strength can also be increased by increasing the number of turns of the coil or by increasing the current flowing through it.