An electric bulb is rated 220V and 100W. when it is operated on 110V, what will be the power consumed?
Why we are using P = V2/R formula while solving and not using P= VI formula
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Answer:
Potential difference across bulb = 220V
Power of bulb = 100 W
=>. V^2/R = 100
220 x 220 / R = 100
R = 22 x 22
R = 484
Therefore, the when operated with 110V bulb,
The power = 110 x 110 / 484
= 25 W
Explanation:
We can't use P= VI because electric current changes with potential difference but resistance doesn't
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