AQA-style topic test · Magnetism and Electromagnetism · Higher tier
Time allowed: 45 minutes
Total: Separate Physics 38 marks · Combined Science 22 marks (skip Questions 05 and 06)
You need: a calculator, a ruler and the equation sheet.
Instructions: Answer all questions on paper. Show your working in calculations. Give answers to an appropriate number of significant figures. Open the mark schemes only when you have finished the whole test.
Question 01
01.1 Describe the magnetic field inside a solenoid carrying a current. [2 marks]
Mark scheme
strong (1)
uniform – the field lines are parallel and equally spaced (1)
01.2 Describe how a student could use a plotting compass to show the shape of the magnetic field around a bar magnet. [2 marks]
Mark scheme
place the compass near the magnet and mark the direction the needle points (1)
move the compass to where the needle last pointed and repeat, then join the marks to draw a field line (1)
01.3 Explain why a compass needle points north when it is far from any magnets. [1 mark]
Mark scheme
the Earth has a magnetic field / the Earth’s core is magnetic (1)
Question 01 total: 5 marks
Question 02
02.1 A wire of length 0.050 m carries a current of 3.0 A. It is at right angles to a magnetic field of flux density 0.40 T.
Calculate the force on the wire.
Use the equation: F = B I l [2 marks]
Mark scheme
F = 0.40 × 3.0 × 0.050 (1)
F = 0.060 N (1)
02.2 A different wire, 15 cm long, is in a magnetic field of 0.20 T. The force on it is 0.12 N.
Calculate the current in the wire. [3 marks]
Mark scheme
15 cm = 0.15 m (1)
0.12 = 0.20 × I × 0.15 (1)
I = 4.0 A (1)
02.3 The wire is turned so that it is parallel to the magnetic field. What happens to the force? [1 mark]
Mark scheme
there is no force / the force becomes zero (1)
02.4 Give the unit of magnetic flux density. [1 mark]
Mark scheme
tesla (T) (1)
Question 02 total: 7 marks
Question 03
03.1 Explain how a simple d.c. electric motor works. Include the role of the split-ring commutator. [6 marks]
Mark scheme
Level 3 (5–6 marks): a clear, logical explanation of why the coil rotates, including the forces on both sides of the coil and why the commutator keeps it turning in one direction.
Level 2 (3–4 marks): the motor effect is used to explain why the coil turns, with some reference to the commutator.
Level 1 (1–2 marks): simple statements about the magnet, the coil or the current.
0 marks: no relevant content.
Indicative content:
• a coil carrying a current is placed in a magnetic field
• each side of the coil experiences a force (the motor effect)
• the current flows in opposite directions on each side, so the forces are in opposite directions (Fleming’s left-hand rule)
• this produces a turning effect, so the coil rotates
• the split-ring commutator reverses the current in the coil every half turn
• so the forces keep acting in the same rotational direction and the coil keeps turning the same way
• increasing the current or the field strength makes the motor turn faster
Question 03 total: 6 marks
Question 04
A relay uses a small current in one circuit to switch on a large current in a second circuit. When the switch in the first circuit is closed, a current flows through a coil wrapped around an iron core. An iron contact near the core is pulled towards it, closing the second circuit.
04.1 Explain how closing the switch turns on the second circuit. [3 marks]
Mark scheme
the current in the coil makes the core an electromagnet (1)
the electromagnet attracts the iron contact (1)
the contacts touch, completing the second circuit (1)
04.2 Why is an iron core used rather than a steel one? [1 mark]
Mark scheme
iron loses its magnetism quickly when the current is switched off (it is an induced magnet), so the relay switches off (1)
Question 04 total: 4 marks
🔷 SEPARATE PHYSICS ONLY – Combined Science students skip Questions 05 and 06
(The generator effect, generators, microphones and transformers are only in Separate Physics.)
Question 05
05.1 A magnet is pushed into a coil, inducing a current. The induced current produces its own magnetic field.
How does this field affect the motion of the magnet? [1 mark]
Mark scheme
it opposes the original change / opposes the motion of the magnet (1)
05.2 An alternator and a dynamo both use the generator effect.
Describe how they are different. [2 marks]
Mark scheme
an alternator has slip rings and produces alternating current (1)
a dynamo has a split-ring commutator and produces direct current (1)
05.3 Explain how a moving-coil microphone converts sound waves into an electrical signal. [3 marks]
Mark scheme
the pressure variations in the sound waves make the diaphragm (and the coil attached to it) vibrate (1)
the coil moves relative to a magnet, so a potential difference is induced (the generator effect) (1)
the induced p.d. varies in the same way as the sound wave (1)
05.4 Give two ways to increase the potential difference produced by a generator. [2 marks]
Mark scheme
any two from (1 each): turn the coil faster · use a stronger magnet · use more turns on the coil
Question 05 total: 8 marks
Question 06
A transformer is connected to the 230 V mains. The primary coil has 2000 turns and the secondary coil has 100 turns. Assume the transformer is 100% efficient.
06.1 Calculate the potential difference across the secondary coil. [3 marks]
Mark scheme
230 ÷ Vs = 2000 ÷ 100 (1)
Vs = 230 × 100 ÷ 2000 (1)
Vs = 11.5 V (1) – allow 12 V
06.2 The current in the secondary coil is 2.0 A. Calculate the current in the primary coil.
Use the equation: Vp × Ip = Vs × Is [3 marks]
Mark scheme
230 × Ip = 11.5 × 2.0 (1)
Ip = 23 ÷ 230 (1)
Ip = 0.10 A (1) – allow error carried forward from 06.1
06.3 Explain how a transformer produces a potential difference across its secondary coil. [2 marks]
Mark scheme
the alternating current in the primary coil produces a changing magnetic field in the iron core (1)
this changing field induces a potential difference across the secondary coil (1)
Question 06 total: 8 marks
END OF TEST. Total: Separate Physics 38 marks · Combined Science 22 marks.
Next: Magnetism – Foundation test · Magnetism topic page · All topic tests
