Q.
In the circuit shown, the electromotive force of the battery is $9\, V$ and its internal resistance is $15\, \Omega$. The two identical voltmeters can be considered ideal. Let $V_{1}$ and $V_{1}'$ be the reading of $1$ st voltmeter when switch is open and closed, respectively. Similarly, let $V_{2}$ and $V_{2}'$ be the reading of $2$ nd voltmeter when switch is open and closed, respectively. Then $\frac{V_{2}'-V_{2}}{V_{1}-V_{1}'}=$
Current Electricity
Solution: