O-LevelPhysicsElectricity5054/22 · Oct/Nov 2025 · Q610 Marks

An electric car is driven by a direct current (d.c.) motor that is powered by a direct current power supply.

(a)Describe how a direct current differs from an alternating current (a.c.).[1]
(b)(i)Fig. 6.1 represents the motor circuit. Point P is a point in the circuit between the motor and the positive terminal of the power supply. Point P is shown to the left of the motor in the circuit diagram. [Figure 6.1] During a time of 120s, the current in the circuit at point P is 41A. Calculate the charge that flows through point P in the time of 120s.[2]
(b)(ii)The current in the circuit is due to the flow of electrons. Each electron carries a charge of magnitude 1.6 × 10⁻¹⁹ C. State the direction which the electrons move past point P and determine the number of electrons that pass point P in 1.0 s.[2]
(c)(i)The power supply for the electric car is a number of batteries, each made from a large number of identical cells. The e.m.f. (electromotive force) of each cell is 3.7V. Define the term 'electromotive force'.[2]
(c)(ii)Each battery consists of 92 cells in series. Calculate the e.m.f. of one battery.[2]
(c)(iii)The power supply is made by connecting 85 of these batteries in parallel. State the e.m.f. of the power supply.[1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2025). The mark or mark type is shown in brackets.

[1] (a) a d.c./ it has one direction or does not (repeatedly) reverse direction or polarity/direction does not change
[1] (b)(i) (Q =) It or 41 × 120
[1] (b)(i) 4.9 × 10³ (C)
[1] (b)(ii) (number =) 41 / 1.6 × 10⁻¹⁹ or 4.9 × 10³ / (120 × 1.6 × 10⁻¹⁹) or 2.6 x 10^N
[1] (b)(ii) 2.6 x 10^20 and towards the positive terminal/away from the motor
[1] (c)(i) (electrical) work done (by a source) in moving charge around a (complete) circuit;
[1] (c)(i) work done (by a source) per unit charge
[1] (c)(ii) (e.m.f. =) 92 × 3.7
[1] (c)(ii) 340 (V)
[1] (c)(iii) same answer as candidate's 6(c)(ii) or 340 (V)

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.