Question

(a) State the relation between potential difference, work done and charge moved.
(b) Calculate the work done in moving a charge of 4 coulombs from a point at 220 volts to another point at 230 volts.

Answer 1

(a) The potential difference between two points in an electric circuit is equal to the amount of work done in moving a unit charge from one point to another point.
$\mathrm{Potential}\mathrm{difference}\left(\mathrm{V}\right)=\frac{\mathrm{Work}\mathrm{done}\left(\mathrm{W}\right)}{\mathrm{Quantity}\mathrm{of}\mathrm{charge}\mathrm{moved}\left(\mathrm{Q}\right)}$
(b) Here:
Potential difference, V = 230 − 220 = 10 V
Charge moved, Q = 4 C
So, using the relation V = W/Q, we have:
W = V $\times$ Q
= 10 $\times$ 4 = 40 J