Explain, in terms of energy, why $V$ is smaller than $E$.
State an equation linking $E$, $I$, $r$ and $V$.
The resistance $R$ of the variable resistor is changed. The way $V$ varies with $I$ is shown in Fig. 6.2.
Use Fig. 6.2 to show how it can be inferred that the e.m.f. of the battery is $2.8\,\text{V}$.
Calculate the internal resistance $r$.
The battery contains $9.2\,\text{kJ}$ of energy. The variable resistor is adjusted so that $V = 2.1\,\text{V}$. Use Fig. 6.2 to:
Calculate resistance $R$.
Calculate the number of conduction electrons passing through the battery in a time of $1.0\,\text{s}$.
Determine the time for the energy in the battery to become equal to $1.6\,\text{kJ}$. (Assume that the e.m.f. of the battery and the current in the battery remain constant.)