Question

A battery of emf $E$ and internal resistance $r$ is connected with an external voltage source (generator) through a resistance $R$ as shown in figure. Choose the correct statements.

• A. In order to charge the battery, the output voltage V of the generator must be greater than E
• B. In order to charge the battery, the output voltage V of the generator must be at least twice of E
• C. The charging current $i$ through the circuit is given by $i=\frac{V-E}{(R+r)}$
• D. The charging current $i$ through the circuit is given by $i=\frac{V}{(R+r)}$

Answer 1

Answer: (A), (C)

For charging a battery the external voltage generator must provide an output voltage $V$ greater than emf of battery $E.$ In charging state
or $I=\left(\frac{V-E}{R+r}\right)$