AQA · GCSE · Physics
Course version: 8463 · Version from Sept 2016
The strength of the magnetic field depends on the distance from the…
Full specification wording
Magnetic fields: The strength of the magnetic field depends on the distance from the magnet. The field is strongest at the poles of the magnet.
How strong the field is depends on where you are.
Checked against the AQA 8463 specification (opens in a new tab) on .
- Point 3 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
How strong the field is depends on where you are. The field lines are packed closest together at the poles, so that is where the field is strongest, and they spread out as you move away, so the field gets weaker with distance from the magnet. The weakening is sharp rather than proportional, so doubling the distance does far more than halve the field. A plotting compass turns most decisively near a pole and iron filings gather most thickly there. The field around a bar magnet is never uniform, which is why 'the field is uniform away from the poles' is a wrong answer; a uniform field is found instead between a pair of opposite magnadur poles or inside a solenoid.
What earns the marks
- Stating that the magnetic field is strongest at the poles of the magnet.
- Stating that the field gets weaker as the distance from the magnet increases.
- Linking the spacing of the field lines to the strength of the field.
- Naming where a uniform field is found instead, between opposite magnadur poles or inside a solenoid.
Common mistakes and how to put them right
Saying the field strength falls in direct proportion to the distance.
Describing the field around a bar magnet as uniform.
Drawing evenly spaced field lines all round a bar magnet.
Assuming the field stops where the drawn lines stop.
Exam tips
- For tick-two questions, find both correct statements before moving on.
- Answer both parts: where the field is strongest and how it changes with distance.
- Show varying strength in a drawing by varying the spacing of the lines.
Try the lesson
The start of the Magnetic fields: The strength of the magnetic field depends on the distance from the magnet. The field is strongest at the poles of the magnet. lesson, made from checked teaching notes for this specification point.
Have a go first
A bar magnet is placed on a bench. At which part of the bar magnet is its magnetic field strongest?
Listen
How strong the field is depends on where you are. The field lines are packed closest together at the poles, so that is where the field is strongest, and they spread out as you move away, so the field gets weaker with distance from the magnet. The weakening is sharp rather than proportional, so doubling the distance does far more than halve the field. A plotting compass turns most decisively near a pole and iron filings gather most thickly there. The field around a bar magnet is never uniform, which is why 'the field is uniform away from the poles' is a wrong answer; a uniform field is found instead between a pair of opposite magnadur poles or inside a solenoid. A strong answer earns marks for these points. stating that the magnetic field is strongest at the poles of the magnet. stating that the field gets weaker as the distance from the magnet increases. linking the spacing of the field lines to the strength of the field. naming where a uniform field is found instead, between opposite magnadur poles or inside a solenoid. Exam tip: For tick-two questions, find both correct statements before moving on.
See it
Key words
Say what each word means before you turn the card.
field strength
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strongest at the poles
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distance from the magnet
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field line spacing
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See every definition
- field strength
- Depends on the distance from the magnet, being strongest at the poles and getting weaker as the distance from the magnet increases.
- strongest at the poles
- The field is strongest at the poles of the magnet, where the field lines are packed closest together.
- distance from the magnet
- The field gets weaker as the distance from the magnet increases, and the weakening is sharp rather than proportional.
- field line spacing
- The spacing of the field lines is linked to the strength of the field, with lines packed closest together at the poles and spreading out as you move away.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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