(a)[2]
State Kirchhoff’s second law in words.
(b(i)(1))[2]
Calculate the total resistance of the two resistors in parallel.
(b(i)(2))[2]
Calculate the current in the battery circuit.
(b(ii))[2]
Show that the internal resistance $r$ has the value $2.5\,\Omega$.
(b(iii))[3]
Determine the ratio $\dfrac{\text{power dissipated in internal resistance } r}{\text{battery total power produced}}$.
(c)[2]
The battery in (b) is now connected to a battery with e.m.f. $7.2\,\text{V}$ and internal resistance $3.5\,\Omega$, as shown. Determine the current in the circuit.