Question

State whether an electric heater will consume more electrical energy or less electrical energy per second when the length of its heating element is reduced. Give reasons for your answer.

Answer 1

The electric heater will consume more electrical energy when the length of its heating element is reduced because resistance is directly proportional to length (R = ρ$\frac{l}{A}$). Hence, resistance will decrease. Power is inversely proportional to resistance (P = $\frac{V^2}{R}$). Hence, power will increase.
Thus, a decrease in resistance means an increase in the power consumed.