4 A washing machine is working normally with both the water heater and the motor switched on. The washing machine is connected to the mains supply by a cable. (a) The current in the live wire in the cable is 13 A. State the size of the current in: (i) the neutral wire in the cable current in neutral wire = … [1] (ii) the earth wire in the cable. current in earth wire = … [1] (b) The insulation on the mains cable is now damaged and, as the washing machine vibrates, the live wire touches the metal casing. (i) Explain how the earth wire and the fuse together prevent any more damage. … … … … … [3] (ii) Explain why it is the live wire into which the fuse is connected. … … … [2] [Total: 7] Question 5 begins over the page

4(a)(i) 13 A B1 4(a)(ii) 0 (A) B1 4(b)(i) resistance of earth wire (and casing) small or disconnects circuit or no electric shock (possible) or stops current B1 current in (live and) earth wire (briefly) B1 fuse (in live wire) blows / melts B1 4(b)(ii) voltage (source) disconnected (by fuse’s blowing) or live voltage immediately next to (switch and blown) fuse or it / live wire at high / maximum voltage / potential B1 no part of the washing machine / casing is live or no current to casing B1

5 Fig. 5.1 shows a method of producing sandpaper using static electricity. paper glue negative metal plate positive metal plate sand sand Fig. 5.1 Glue is sprayed on to moving paper. The sticky paper then passes between two metal plates. One of the plates is positive and the other plate is negative. There is an electric field between the plates. (a) On Fig. 5.2, draw the electric field between the two metal plates. Show the direction of the electric field. negative metal plate positive metal plate Fig. 5.2 [2] (b) Grains of sand are present just below the sticky paper. Each grain of sand is a conductor of electricity. Fig. 5.3 shows two layers of sand grains in the space between the two plates. negative metal plate positive metal plate sand grains sticky paper Fig. 5.3 (i) Explain, using ideas about the movement of charge, why the top layer of sand becomes positively charged. … … [1] (ii) State why the top layer of sand moves towards the sticky paper. … … [1] (c) A student receives an electric shock by walking across a certain type of carpet and then nearly touching a piece of earthed metal with his hand. The potential difference between the hand and the metal is 2000 V and the charge transferred is 4.0 × 10−4 C. Calculate the energy transferred when the spark jumps across the air gap from the metal onto his hand. energy = … [2] [Total: 6]

5(a) at least three straight lines perpendicular to plates B1 arrow on at least one line from positive to negative plate B1 5(b)(i) electrons / negative charge (on sand / grains) move to(wards) the positive plate / downwards / to(wards) or into the bottom layer B1 5(b)(ii) positive (sand grain) attracted to or by negative (plate) B1 5(c) (E) = QV numerical or algebraic C1 0.8(0) J A1 (a) To earn the first mark, draw at least three straight electric field lines perpendicular to the plates. For the second mark, add an arrow on at least one line pointing from the positive plate to the negative plate. (b)(i) You must explain that electrons or negative charges on the sand grains move towards the positive plate, downwards, or into the bottom layer. (b)(ii) To earn this mark, state that the positively charged sand grains are attracted to or by the negative plate. (c) First, show the formula E = QV or substitute values into it. Then, correctly calculate the energy as 0.80 J.

5 A plastic rod that is initially neutral is rubbed with a woollen cloth. After the rod has been rubbed, it is positively charged. (a) (i) Explain, in terms of particles, why the rod is now positively charged. … … [1] (ii) State what happens to the woollen cloth. … [1] (b) An uncharged, conducting sphere is suspended from an insulating thread. The positively charged rod is placed near to the sphere, as shown in Fig. 5.1. rod sphere insulating thread Fig. 5.1 (i) On Fig. 5.1, draw the distribution of charge on the sphere. [2] (ii) Explain why the sphere is pulled towards the rod. … … … … [2] [Total: 6]

5(a)(i) electrons are transferred from rod (on to cloth) B1 5(a)(ii) it / the cloth becomes negatively charged B1 5(b)(i) more negative (than positive) signs on left of sphere and more positive (than negative) signs on right M1 equal numbers of positive and negative signs and six or fewer A1 5(b)(ii) negative charges/electrons (on sphere) attracted by positive charges (on rod) B1 force of attraction greater than repulsion (of positive charges) or distance between negative (on sphere) and positive charges (on rod) less than distance between positive and positive B1

5 EITHER Fig. 5.1 shows a circuit that contains a direct current (d.c.) power supply, a light-dependent resistor (LDR), two fixed resistors, M and N, and two ammeters. A A ammeter 2 ammeter 1 M + – N Fig. 5.1 (a) The reading on ammeter 1 is 1.6 mA. Calculate the time taken for a charge of 7.2 C to pass through ammeter 1. time = … [2] (b) Some time later, the brightness of the light incident on the LDR decreases. Explain what happens to: (i) the reading on ammeter 2 … … [1] (ii) the time taken for a charge of 7.2 C to pass through ammeter 1. … … … [2] [Total: 5] OR Fig. 5.2 shows the symbol for an electronic circuit component. Fig. 5.2 (a) State the name of the component shown in Fig. 5.2. … [1] (b) Fig. 5.3 is the diagram of a circuit that includes this component, a light-dependent resistor (LDR) and a relay. + – M mains supply relay motor 6.0 V Fig. 5.3 The motor in Fig. 5.3 is part of the pump in a garden fountain. In the dark, the pump does not work. In the morning, the brightness of the light incident on the LDR increases. (i) State what happens to the LDR. … [1] (ii) Explain why the motor switches on. … … … … [3] [Total: 5]

5E(a) (t =) Q / I or 7.2 / 0.0016 or 7.2 / 1.6 or 4.5 × 10N C1 4500 s A1 5E(b)(i) does not change and p.d. / voltage across resistor N does not change / ammeter 2 is not in the branch that contains the LDR B1 5E(b)(ii) resistance of LDR increases or current (in M / in ammeter 1) decreases B1 time taken increases B1 5O(a) (bipolar npn) transistor B1 5O(b)(i) its resistance decreases or current in the LDR increases B1 5O(b)(ii) base current or base-emitter voltage increases B1 there is now a current in the relay coil or transistor switches (circuit) on or coil / core magnetised B1 relay coil attracts the relay switch / closes switch (in the mains circuit) B1

5 An electron has mass. Where does a stationary electron experience a force? A in an electric field only B in a gravitational field only C in a gravitational field and an electric field only D in a gravitational, electric and magnetic field

Answer: C To earn the mark, a student must state that a stationary electron experiences a force in a gravitational field and an electric field only.

Cambridge O Level Physics · 5054

O-Level Physics (5054) Electricity and magnetism past paper questions

Revise O-Level Physics (5054) — Electricity and magnetism with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

365 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Electricity and magnetism in O-Level Physics 5054 exams, 2020–2025

Across 2020–2025, Electricity and magnetism accounted for 335 questions worth 1,281 marks in Cambridge O Level Physics (5054) papers.

By year
Year	Questions	Marks
2020	50	207
2021	61	239
2022	64	200
2023	57	206
2024	51	198
2025	52	231

Most-tested subtopics

4.2.4 Resistance550 marks
4.2.3 Electromotive force and potential difference536 marks
4.3.2 Series and parallel circuits483 marks

Appears in

Paper 1 · 217 qs
Paper 2 · 64 qs
Paper 3 · 25 qs
Paper 4 · 29 qs

All most-tested Physics topics

2021 Oct/Nov · Paper 2 · Q4 · 7 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 2 · Q5 · 6 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 2 · Q5 · 6 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 2 · Q5 · 10 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 1 · Q5 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q5
Answer: C
Get Steven’s plain-English explanation