Creating a uniform magnetic field
3 marks · NormalExplain how to use two permanent bar magnets to create a uniform magnetic field. Include what you would observe with iron filings placed between them.
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Also accept: Place two bar magnets with opposite poles (north facing south) close together but with a gap between their poles. The field in the gap is uniform, as shown by iron filings forming straight, parallel lines.
Common mistakes: Using like poles; Iron filings not forming straight lines; Not mentioning opposite poles.
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Marking points
M1 · 1 mark · States to place two bar magnets with their opposite poles (N and S) facing each other, with a small gap between.
B1 · 1 mark · Describes that the field between the magnets is uniform.
B2 · 1 mark · Correctly describes the appearance of iron filings (straight, parallel lines) in the region between the facing poles.
Worked solution
To produce a uniform field, place two bar magnets so their opposite poles (north and south) face each other, with a small gap. The region between these poles creates a uniform magnetic field. Iron filings sprinkled in this area align to form straight, parallel lines evenly spaced between the magnet poles.