Question

A battery consists of a variable number $n$ of identical cells (having internal resistance $r$ each) which are connected in series. The terminal of the battery are short circuited and the current $I$ is measured. Which of the graph shows the correct relationship between $I$ and $n?$

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

Equivalent Emf, $\epsilon =n\epsilon$
Equivalent resistance, $R=nr$
$\therefore \text{Current,}I=\frac{\epsilon }{R}=\frac{n\epsilon }{nr}$=$\frac{\epsilon }{r}$
$I$ is independent of $\epsilon$