Question

If the potential difference between the ends of a fixed resistor is halved, the electric power will become:

(a) double
(b) half
(c) four times
(d) one-fourth

Answer 1

(d) one-fourth
Since P = $\frac{{\mathrm{V}}^2}{\mathrm{R}}$, when the potential difference is halved, the power becomes one-fourth.