State Kirchhoff’s second law for a circuit.
A battery is connected in parallel with two lamps A and B, as shown in Fig. 5.1. The battery has electromotive force (e.m.f.) $6.8\ \text{V}$ and internal resistance $r$. The $I\text{-}V$ characteristics of lamps A and B are shown in Fig. 5.2. The potential difference across the battery terminals is $6.0\ \text{V}$.
Use Fig. 5.2 to demonstrate that the current in the battery is $0.40\ \text{A}$.
Calculate the battery's internal resistance $r$.
Determine the ratio $\frac{\text{resistance of lamp A}}{\text{resistance of lamp B}}$.
Use Fig. 5.2 to demonstrate that the current in the battery is $0.40\,\text{A}$.
Calculate the battery's internal resistance $r$.
Determine the ratio $\dfrac{\text{resistance of lamp A}}{\text{resistance of lamp B}}$.
Determine the total power produced by the battery.
Determine the efficiency of the battery in the circuit.