Physics 9702 · AS & A Level · Potential difference and power
Potential difference and power — practice question
Fig. 7.1 depicts two resistors in series with a cell whose electromotive force (e.m.f.) is $1.50\,\text{V}$ and whose internal resistance is $0.28\,\Omega$. One resistor has resistance $1.0\,\Omega$. The other resistor has resistance $R$. The terminal potential difference (p.d.) across the cell is $1.36\,\text{V}$.
(a(i))[2]
Show that the circuit current $I$ is $0.50\,\text{A}$.
(a(ii))[2]
Calculate the total resistance of the two resistors.
(a(iii))[1]
Use your answer in (a)(ii) to find resistance $R$.
(b(i))[1]
Complete the circuit diagram on Fig. 7.2 to represent this arrangement.
(b(ii))[2]
Explain, without calculation, whether the terminal p.d. across the cell is now less than, equal to, or greater than $1.36\,\text{V}$.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “finds $V = 1.50 - 1.36 = 0.14\ \text{V}$” …