A room heater is rated 400 W, 220 V. If the supply voltage drops to 200 V, what will be the power consumed (approximately) ?NEET 2026 (Cancelled)

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The resistance of the room heater is given by $R = \frac{V ^{2}}{P}$

Substituting the rated values, $R = \frac{22 0 ^{2}}{400} = \frac{48400}{400} = 121Ω$

When the supply voltage drops to $V^{'} = 200$ V, the power consumed is $P^{'} = \frac{V ^{'2}}{R}$

$P^{'} = \frac{20 0 ^{2}}{121} = \frac{40000}{121} \approx 330.57$ W

Therefore, the power consumed is approximately $331$ W.

Answer: $331$ W

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