A room heater is rated 400 text{ W}, 220 text | vedclass

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Question

(C) The resistance $R$ of the heater is constant.
Using the formula $R = \frac{V^2}{P}$, we calculate $R = \frac{220^2}{400} \Omega$.
The new power

Vedclass · Accepted Answer

$331$

Vedclass · Answer

(C) The resistance $R$ of the heater is constant.
Using the formula $R = \frac{V^2}{P}$, we calculate $R = \frac{220^2}{400} \Omega$.
The new power consumed $P'$ at the new voltage $V' = 200 	ext{ V}$ is given by $P' = \frac{(V')^2}{R}$.
Substituting the value of $R$, we get $P' = \frac{(V')^2 \cdot P}{V^2} = \frac{200^2 	imes 400}{220^2}$.
$P' = \frac{40000 	imes 400}{48400} = \frac{16000000}{48400} \approx 330.57 	ext{ W}$.
Rounding off to the nearest integer, we get $331 	ext{ W}$.

$A$ room heater is rated $400 \text{ W}$, $220 \text{ V}$. If the supply voltage drops to $200 \text{ V}$, what will be the power consumed (approximately) (in $\text{ W}$)?

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