Magnetism and Electromagnetism

IGCSE Edexcel Physics
6.1–6.16 Magnetism, Motor Effect and Induction
Key Concepts: Magnets have fields and can induce magnetism. Currents create magnetic fields and experience forces. Moving conductors in magnetic fields induce voltage.

Section A: Units

1. State the SI units for current, voltage and power. [3]

Section B: Magnetism

2. Describe how magnets interact and what magnetic field lines show. [3]
3. Compare magnetically hard and soft materials with one use for each. [3]
4. Explain how magnetism can be induced in some materials by a magnetic field. [2]
5. Describe a practical to show the magnetic field pattern around a bar magnet and between two magnets. [3]
6. Describe how to use two permanent magnets to produce a uniform magnetic field. [2]

Section C: Electromagnetism and Motor Effect

7. Describe the magnetic field around a current-carrying wire and a solenoid. [3]
8. Explain the motor effect and use Fleming's left-hand rule to predict force direction. [3]

Section D: Electromagnetic Induction

9. Describe two ways to induce a voltage in a coil. [2]
10. Explain how a generator produces electricity and state two factors that increase induced voltage. [4]
Total marks: 30

Mark Scheme

1. A, V, W [3]
2. Like poles repel, unlike attract; field lines show direction (N to S) and strength (spacing) [3]
3. Hard materials retain magnetism (permanent magnets); soft materials easily magnetised/demagnetised (electromagnets) [3]
4. Magnetic field can align domains so material becomes magnetized [2]
5. Use iron filings or plotting compass to map field lines around one magnet and between two magnets [3]
6. Place two magnets with unlike poles facing and equal spacing to create near-uniform field [2]
7. Field is circular around wire; solenoid gives uniform field inside like a bar magnet [3]
8. Motor effect: force on current in magnetic field; left-hand rule relates field, current, force [3]
9. Move coil/conductor through field; change magnetic field through coil [2]
10. Relative motion between coil and magnet induces voltage; increase speed, number of turns, magnetic field strength [4]