Q. If current in an electric bulb changes by 1%, then the power will change by
A) 1%
B) 2%
C) 4%
D) $\frac{1}{2}\%$
Explanation
(b) $P = i^{2}R \Rightarrow \frac{\mathrm{\Delta}P}{P} = \frac{2\mathrm{\Delta}i}{i}\ \ \ \ \lbrack R \rightarrow Constant\rbrack$
$\Rightarrow \ $% change in power $= 2 \times \%\ $change in current
$= 2 \times 1 = 2\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.