A student places two bar magnets on a table with their north poles facing each other. Describe what happens between the two magnets and explain, using the idea of magnetic field lines, why this occurs.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
The two magnets repel each other.
Like poles repel – the north pole of one magnet repels the north pole of the other.
Magnetic field lines leave a magnet at its north pole, curve around the outside of the magnet and re‑enter at the south pole.
Between the two north poles the field lines run in opposite directions – they point towards each other and cannot merge or cross.
Because the field lines are forced into this opposing arrangement, the magnetic pressure between the poles is higher than outside, producing a repulsive force that pushes the magnets apart.
Like poles repel – the north pole of one magnet repels the north pole of the other.
Magnetic field lines leave a magnet at its north pole, curve around the outside of the magnet and re‑enter at the south pole.
Between the two north poles the field lines run in opposite directions – they point towards each other and cannot merge or cross.
Because the field lines are forced into this opposing arrangement, the magnetic pressure between the poles is higher than outside, producing a repulsive force that pushes the magnets apart.
Examiner tips
- Use the phrase "like poles repel" to hit the key point. Show the field‑line direction (north to south outside the magnet). Explain that field lines cannot cross – this justifies the repulsion. Keep the answer concise to fit the 5 marks.
Common mistakes
- Confusing attraction with repulsion – writing that the magnets attract. Forgetting to mention that field lines run from north to south outside the magnet. Saying the field lines merge or cross, which is incorrect.
Mark scheme (5 marks)
- The two magnets repel each other
- Like poles repel / north pole repels north pole
- Magnetic field lines travel from north to south outside the magnet
- Between the two north poles, the field lines point in opposite directions / towards each other / field lines cannot merge or cross
- This opposing arrangement of field lines produces a repulsive force / the magnets are pushed apart because the field lines cannot pass through each other
Key terms in this question
magnetic field lines · north pole
Related
- All Eduqas A-Level Physics revision notes →
- How to answer a "Describe and Explain" question →
- Decode the mark scheme abbreviations →
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