Question

A cell of e.m.f. E is connected across a reistance R. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be 

(a)  [2(E–V)V]/R

(b)  [2(E–V)/V]R

(c)  [(E–V)/V]R

(d)  (E–V)R

Answer 1

Correct option (c) [(E–V)/V]R

Explanation:

Let r be the internal resistance of the cell. 

Terminal potential difference (V) < EMF of a cell (E).