Q34 of 330 Page 20

A current of 200 mA flows through a 4 KΩ resistor. What is the p.d. across the resistor?

Given,

I = 200mA = 200 × 10^-3A

R = 4000 ohms

So, V = 200 × 10^-3A × 4×10³

V= 800 volts

The graph between V and I for a conductor is a straight line passing through the origin.

(a) Which law is illustrated by such a graph?

(b) What should remain constant in a statement of this law?

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

What happens to the resistance as the conductor is made thicker?

If the length of a wire is doubled by taking more of wire, what happens to its resistance?