A bulb rated at $60\text{W}$ is operated on a $240\text{V}$ mains supply. (a) Calculate the current drawn by the bulb. (b) Determine the resistance of the filament.

Step-by-step solution

1. Use the power formula $P=VI$ to find current: $I=P/V$.
2. Substitute $P=60\text{W}$ and $V=240\text{V}$ to get $I=60/240=0.25\text{A}$.
3. Now use Ohm's law $V=IR$ to find resistance: $R=V/I$.
4. Substitute $V=240\text{V}$ and $I=0.25\text{A}$ to obtain $R=240/0.25=960\Omega$.

Concept tested: Power and resistance of appliances

Published 23 August 2026 · How this solution was prepared and checked

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