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A light bulb is rated at 200 W for a 220 V supply. Find the resistance of the bulb.

Asked in GUJCET 2022 · Rated bulbs and appliances

Answer: (3) 242 Ω

Step-by-step solution

Given: P = 200 W at V = 220 V.

Idea: P = (V²)/R, so R = (V²)/P.

R = (220²)/(200) = (48400)/(200) = 242 Ω.

On the same supply a higher-power bulb has a lower resistance; a 100 W bulb has 484 Ω.

Why the other options are wrong

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