Q. In an $RC$ circuit while charging, the graph of $\ln i$ versus time is as shown by the dotted line in the diagram figure, where $i$ is the current. When the value of the resistance is doubled, which of the solid curve best represents the variation of $\ln i$ versus time
A) $P$
B) $Q$
C) $R$
D) $S$
Explanation
(b) In case of $RC$ circuit $i = \frac{E}{R}e^{- t/RC}$
$\therefore\log_{e}{i = - \frac{t}{RC} + \log_{e}\frac{E}{R}}$
When $R$ is doubled, the slope of the curve increases. Further at $t = 0,$ the current will be less for an increased value of resistance
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.