Question

You are given a dry cell, a torch bulb with holder, wires and crocodile clips. How would you use them to distinguish between samples of metals and non-metals?

Answer 1

Take a torch bulb fitted with a holder and connect it to a dry cell using connecting wires, as shown in the figure below. There is a gap between the ends of the crocodile clips A and B; so, no current flows in the incomplete circuit. Hence, the bulb does not light up.

Metals are good conductors of electricity. Hence, if metal samples are inserted between clips A and B, the samples will allow an electric current to pass through them, and the bulb will light up. But non-metals do not conduct electricity. Hence, non-metal samples do not allow electric current to pass through them, and the bulb will not glow.