Magnetism questions

Magnetism syllabus

Questions on magnetism can test recall, calculations, explanations, diagrams, data handling and practical skills. You should be able to:

• 6.2 know that magnets repel and attract other magnets and attract magnetic substances
• 6.3 describe the properties of magnetically hard and soft materials
• 6.4 understand the term 'magnetic field line'
• 6.5 know that magnetism is induced in some materials when they are placed in a magnetic field
• 6.6 practical: investigate the magnetic field pattern for a permanent bar magnet and between two bar magnets
• 6.7 describe how to use two permanent magnets to produce a uniform magnetic field pattern

How to answer magnetism questions

1. Add arrows to field lines and distinguish magnetic field direction from force direction.
2. State what changes in the field or conductor before explaining an induced voltage.
3. Apply the left-hand rule systematically and describe how reversing current or field reverses force.
4. For transformer calculations, label primary and secondary quantities before using the turns ratio.

Magnetism example questions and worked answers

These examples show how information in a diagram, graph or experimental context becomes part of a complete exam answer.

Example 1: Interpreting magnetic field patterns

June 2018 · Paper 1P · Question 9(a)

Question 1

Which diagram shows the correct magnetic field pattern between the north poles of two bar magnets?

Final answer

D. The field lines point away from both north poles and curve away from the gap as the poles repel.

Mark scheme points

1. M1 Select diagram D, which shows repulsion and the correct field-line direction.

Explanation

Magnetic field lines point away from a north pole. Since the two facing poles are both north poles, they repel, so the field lines bend away from the space between them. Diagram D shows both features.

Common mistakes

• Check both the shape of the lines and their arrows: lines curving away from the gap are not enough if the arrows point towards the north poles.

Example 2: Testing a magnetic-field relationship

June 2019 (R) · Paper 1P · Question 11(c)

Question 2

A student investigates the magnetic fields produced by magnets.

Magnetic field strength can be measured in units of milli-tesla (mT).

A student uses a different magnet.

The student measures the magnetic field strength at different distances from the north pole of this magnet.

The graph shows his results.

The student concludes that his results obey this relationship.

magnetic field strength × distance² = constant

Use data from the graph to deduce whether the student’s results support this conclusion.

Final answer

At 30 mm, the field strength is about 2.3 mT, giving 2.3 × 30² = 2070 mT mm². At 50 mm, it is about 0.8 mT, giving 0.8 × 50² = 2000 mT mm². These values are approximately equal, so the results support the student’s conclusion.

Mark scheme points

1. M1 Read a pair of distance and field-strength values from the graph.
2. M2 Correctly substitute those values into field strength × distance² to find the constant.
3. M3 Use a different pair of graph readings and correctly calculate the constant again.
4. M4 State whether the results support the conclusion by comparing the two constants.

Explanation

To test whether the product is constant, choose two different points on the graph and calculate field strength × distance² for each. For example:

At 30 mm: 2.3 mT × (30 mm)² = 2070 mT mm²
At 50 mm: 0.8 mT × (50 mm)² = 2000 mT mm²

The calculated values are close, allowing for approximate readings from the graph. Therefore, the data support the proposed relationship.

Common mistakes

• Many candidates scored zero because they did not refer to any data. Include two graph readings, calculate both products, and compare them.

Practise Magnetism questions

Build a focused practice set from this part of the Edexcel IGCSE Physics syllabus.