Question

A p.d. of 10 V is needed to make a current of 0.02 A flow through a wire. Wire p.d. is needed to make a current of 250 mA flow through the same wire?

Answer 1

wire.

So potential difference, V = 10 V

Current, I = 0.02 A

Resistance of the wire, R = V/I

R = 10/0.02 = 500 Ω

The resistance will remain the same unless the wire is changed.

Now, to make a current of 250 mA to flow through the wire, the potential difference required is:

V = IR

V = 250 x 10^-3 x 500

V = 125 V

So a potential difference of 125 V is needed to make a current of 250 mA flow through the wire.