Q. A battery of emf $E$ has an internal resistance $r.$ A variable resistance $R$ is connected to the terminals of the battery. A current $i$ is drawn from the battery. $V\ $is the terminal potential difference. If $R$ alone is gradually reduced to zero, which of the following best describes $i$ and $V$?
A) $i\ approaches\ zero,V\ approaches\ E$
B) $i\ \ approaches\frac{E}{r},\ V\ approaches\ zero$
C) $i\ approaches\frac{E}{r},V\ approaches\ E$
D) $i\ approaches\ infinity,V\ approaches\ E$
Explanation
(b) Current, $i = \frac{E}{R + r}$ when R decreases to 0, $i = \frac{E}{r}$.
Similarly, potential difference $V = iR$ when R decreases to 0,
$V = 0$.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.