Question

A cell of e.m.f. 1.8 V is connected to an external resistance of 2 Ω, when p.d. recorded at the ends of resistance is 1.6 V. Calculate the internal resistance of the cell.

Answer 1

E = 1.8 V; V = 1.6 V; R = 2 Ω; r = ?

\[r = \frac{R(E - V)}{V}\]

\[= \frac{2(1.8 - 1.6)}{1.6}\]

\[= \frac{2 \times 0.2}{1.6}\]

\[= 0.25\text{ Ω}\]