A wire carries a current of 0.2 A for 10 seconds. If the potential difference between the two ends of the wire is 20 V, find the work done in this process.

Solution: Data : I = 0.2 A, t = 10 s, V = 20 V, W = ?

I = Q/t and V = W/Q

∴ W = VQ = VIt = 20 V  × 0.2 A × 10 s = 40 J

The work done = 40 J