An electric bulb is rated $220\, volt$ and $100\, watt$. Power consumed by it when operated on $110\, volt$ is ............. $watt$
A$50$
B$75$
C$40$
D$25$
AIEEE 2006, Medium
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D$25$
d (d)Resistance of the bulb = $\frac{{{V^2}}}{{{P_{Ratate}}}} = \frac{{220 \times 220}}{{100}} = 484\,\Omega $
When connected with $110 \,V$, the power consumed ${P_{Consumed}} = \frac{{{V^2}}}{R} = \frac{{110 \times 110}}{{484}} = 25\,W$
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