Question:
If the electric current in a lamp decreases by $5 \%,$ then the power output decreases by
If the electric current in a lamp decreases by $5 \%,$ then the power output decreases by
Updated On: Apr 30, 2024
- 2.5 $\% $
- 10 $\% $
- 5 $\% $
- 20 $\% $
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The Correct Option is B
Solution and Explanation
Power of lamp
$\hspace15mm P=i^2R $
or $\hspace15mm \frac {dP}{P}=2 \frac {? i}{i}= 2 \times 5 \% \hspace5mm \bigg (\because \frac {? i}{i}=5 \% \bigg ) $
$\hspace15mm =10 \% \$ decrease
$\hspace15mm P=i^2R $
or $\hspace15mm \frac {dP}{P}=2 \frac {? i}{i}= 2 \times 5 \% \hspace5mm \bigg (\because \frac {? i}{i}=5 \% \bigg ) $
$\hspace15mm =10 \% \$ decrease
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