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JEE Main 2021 (25 Jul, Shift 1) · Electrical Power & Heating Effect

Electrical Power & Heating Effect question from JEE Main 2021 (25 Jul, Shift 1)

Q35JEE Main 2021 · 25 JUL · SHIFT 1Medium

Electrical Power & Heating Effect

An electric bulb rated as 200 W at 100 V is used in a circuit having 200 V supply. The resistance 'R' that must be put in series with the bulb so that the bulb delivers the same power is _____________ $\Omega$ .

Numerical answer type. Work it out, then open the answer.

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Answer: 50

$R_b = \frac{100^2}{200} = 50\ \Omega$ ; rated current $I = \frac{200}{100} = 2$ A.
Total resistance at 200 V: $\frac{200}{2} = 100\ \Omega$ .
$R = 100 - 50 = 50\ \Omega$ .

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