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An electric bulb marked as 50w -200v is connected across a 100v supply. The power consumed by the bulb at present isA) 37.5wB) 25wC) 12.5wD) 10w |
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Answer» Power of bulb (P) = V^2/R Where V is the voltage and R is the resistance of the bulb. Here Powe =50W when voltage = 200V. So R =V^2/P=200^2/50=800ohm. When supply voltage is 100V then Power =100^2/800=12.5W |
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