In Fig. 7.1, a student assembles the circuit. The diagram includes a $12\,\text{V}$ supply, an ammeter, a $6.0\,\Omega$ resistor with current $0.50\,\text{A}$, and a parallel arrangement of resistor $R$ carrying current $I_1$ together with a $20\,\Omega$ resistor carrying current $I_2$.
(a)[1]
Determine the ammeter reading.
(b)[2]
Calculate the potential difference (p.d.) across the $6.0\,\Omega$ resistor in the circuit.
(c)[1]
Show that the p.d. across the $20\,\Omega$ resistor comes to $9.0\,\text{V}$.
(d)[3]
Calculate the resistance of resistor $R$ in the circuit.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Answer: 0.50 A” …