Free Magnetic effect of current & motors questions for IGCSE Physics (0625), part of Electricity & magnetism. Each question has the answer and the marking points an examiner would look for.
Generate a full Magnetic Effect of Current & Motors worksheet →All Electricity & magnetism questionsA simple d.c. motor is rotating clockwise.
Which changes, made one at a time, would make the motor rotate anticlockwise?
1 reversing the current in the coil
2 reversing the poles of the magnet
3 reversing both the current and the poles of the magnet
Answer: B
What is the purpose of the split-ring commutator in a d.c. motor?
Answer: D
A beam of electrons passes through a magnetic field.
Explain why the beam is deflected.
State how the deflection changes if the field is made stronger.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | moving charges in field experience force the electrons are moving charges B1 a magnetic field exerts a force on moving charges B1 | 2 |
| (b) | greater deflection the deflection increases B1 | 1 |
A loudspeaker uses the motor effect.
Explain how a loudspeaker produces sound.
State how a higher-pitched sound is produced.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | a.c. in coil in magnetic field; force changes direction; cone vibrates an alternating current passes through a coil in a magnetic field B1 the force on the coil changes direction rapidly B1 the coil and cone vibrate, producing sound waves B1 | 3 |
| (b) | higher frequency a.c. increase the frequency of the alternating current B1 | 1 |
A wire carrying a current is placed between the poles of a magnet. The wire moves.
Explain why the wire moves.
State two ways to reverse the direction of the force.
State the rule used to find the direction of the force.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | interaction of magnetic fields the current produces a magnetic field around the wire B1 this interacts with the magnet’s field, producing a force B1 | 2 |
| (b) | reverse current; reverse field reverse the current B1 reverse the magnetic field (swap the poles) B1 | 2 |
| (c) | Fleming’s left-hand rule Fleming’s left-hand rule B1 | 1 |
This question is about the motor effect.
A wire carrying a current is placed between the poles of a magnet. State three ways of increasing the force on the wire.
State the rule used to predict the direction of the force, and what each finger represents.
State two ways of reversing the direction of the force.
Explain the purpose of the split-ring commutator in a d.c. motor.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | increase current; stronger magnet; longer wire in field increase the current B1 use a stronger magnet B1 increase the length of wire in the field B1 | 3 |
| (b) | Fleming’s left-hand rule; thumb motion, first finger field, second finger current Fleming’s left-hand rule B1 thumb = force (motion), first finger = field, second finger = current B1 | 2 |
| (c) | reverse the current; reverse the magnetic field reverse the current B1 reverse the magnetic field (swap the poles) B1 | 2 |
| (d) | reverses current every half turn so coil keeps turning same way reverses the direction of the current in the coil every half turn B1 so the turning force always acts in the same direction B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in