A student assembles the circuit in Fig. 7.1. The electromotive force (e.m.f.) of the battery is $6.0\,\text{V}$. Variable resistor X is adjusted to $1.8\,\Omega$.
(a(i))[3]
Determine the overall resistance of the circuit.
(a(ii))[2]
Determine the current shown by the ammeter.
(b(i))[1]
State what is meant by the potential difference (p.d.) across a component in a circuit.
(b(ii))[1]
Add the symbol for the component that measures the p.d. across the $2.8\,\Omega$ resistor to Fig. 7.1.
(b(iii))[2]
The resistance of X is increased. Explain why the p.d. across the $2.8\,\Omega$ resistor decreases.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Applies 1/RT = 1/R1 + 1/R2 (or equivalent)” …