A dry cell delivering 2 A has terminal voltage 1.41V. What is the internal resistance of the cell if its open–circuit voltage is 1.59 V?
Answer & explanation
Correct answer: option 4
Open circuit voltage = E = 1.59V
$ V = E - Ir $
$ \Rightarrow 1.41 = 1.59 - 2 r $
$\Rightarrow r = \frac{0.18}{2} = 0.09 \Omega$