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प्रश्न
A light bulb is rated at 120 W for a 220 V a.c. supply. Calculate the resistance of the bulb.
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उत्तर
Power of the bulb, P = 120 W
Voltage, V = 240 V
The resistance of the buld is given as
`R = V^2/P = (240^2)/120 = 480 Omega`
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