Two bulbs of (40 W, 200 V), and (100 W, 200 V). Then correct relation for their resistances (a) R40 R100 (c) R40 = R100 (d) no relation can be predicted.

Answer: (b). R = V²/P; same rated voltage, so R ∝ 1/P. R₄₀ = (200²)/(40) = 1000 Ω, R₁₀₀ = (200²)/(100) = 400 Ω. So the answer is (b) R₄₀ > R₁₀₀.

Two bulbs of (40 W, 200 V), and (100 W, 200 V). Then correct relation… | NEET 2000 (AIPMT)

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Electrical Power & Heating Effect

Two bulbs of (40 W, 200 V), and (100 W, 200 V). Then correct relation for their resistances

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Answer: (b)

$R = \frac{V^2}{P}$ ; same rated voltage, so $R \propto \frac{1}{P}$ .
$R_{40} = \frac{200^2}{40} = 1000\ \Omega$ , $R_{100} = \frac{200^2}{100} = 400\ \Omega$ .
So the answer is (b) $R_{40} > R_{100}$ .