Question

You are provided with a $5cm$ long and $\frac{1}{2}cm$ thick soft iron rod. How will you convert it into electromagnet?

Answer 1

A magnet which operates only when electric current flows around iron is called electromagnet.

Making of an electromagnet:

1. An iron nail about $5cm$ long and $\frac{1}{2}cm$ winded over it an insulated copper wire.
2. Bare the ends of copper wire from insulation.
3. Fix each end of bare copper wire on the terminals of dry cell.
4. Hold the copper wire at terminals with cello-tape.

From above arrangement,

1. It is observed that iron paper clips cling to the wire.
2. This proves that iron nail changes to magnet when current flows around it.
3. Remove the wire from the dry cell.
4. It is found that paper clips fall down.
5. From this we conclude that the iron nail behaves like a magnet only as long as the current flows around it.
6. The strength of the electromagnet can be increased either by increasing the current in the coil or by increasing the number of turns of the coil.

Thus, in this way we can convert a iron rod into a electromagnet.