(a(i))[3]
Describe the way the transformer works.
(a(ii))[2]
The transformer’s output voltage is alternating, so it cannot be applied directly as a d.c. power supply. In the space below, draw the symbol of a component that lets current pass in only one direction and give the component’s name.
(b(i))[2]
Explain what the term e.m.f. means.
(b(ii)-1)[1]
Calculate the resultant e.m.f. in the circuit. The power supply has an e.m.f. of $5.0\,\text{V}$ and the battery has an e.m.f. of $3.7\,\text{V}$.
(b(ii)-2)[2]
Calculate the current flowing in the circuit.
(b(ii)-3)[3]
The current in the circuit stays constant while the battery is being charged. Calculate the charge that passes through the resistor in $1.5$ hours.
(c)[2]
Explain why the battery charger does not need to be earthed.