Question

n identical cells, each of emf E and internal resistance r, are joined in series to form a closed circuit. The potential difference across any one cell is 

(a) zero 

(b) ℰ

(c) ℰ / n 

(d) (n - 1/n) ℰ

Answer 1

Correct Answer is: (a) zero 

Current in the circuit is i = nℰ / nr = ℰ / r.

The equivalent circuit of one cell is shown in the figure above. Potential difference across the cell equals

V_A - V_B = -ℰ + ir = -ℰ + ℰ / r. r =0.