Magnetism
5 marks · NormalA technician needs to create a region with a strong, uniform magnetic field for a physics experiment.
Describe how two permanent bar magnets should be arranged to produce a uniform magnetic field.
Sketch or describe the magnetic field lines in the region between the two magnets.
Explain why the field is considered uniform in this region.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Place the bar magnets with their opposite poles facing each other and with a gap between them. · must show Opposite poles face each other, Gap between magnets
(b) The magnetic field lines in the gap are straight, parallel, and evenly spaced, running from the north pole of one magnet to the south pole of the other. · must show Straight lines, Parallel and evenly spaced
(c) The field is uniform because the field lines are parallel and equally spaced, showing the field strength and direction are the same throughout the region. · must show Parallel/equally spaced lines, Same strength and direction
Common mistakes: Describing magnets touching or parallel the wrong way; Not mentioning opposite poles facing
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States opposite poles must face each other.
B2 (a) · 1 mark · Includes there should be a gap (not touching) for the uniform region.
B1 (b) · 1 mark · Mentions field lines are straight and parallel.
B2 (b) · 1 mark · Mentions lines run from north to south.
B1 (c) · 1 mark · Explains uniform means field strength and direction are constant (parallel, equally spaced lines).
Worked solution
(a) The bar magnets should be arranged with a gap between their opposite poles facing each other — for example, north facing south.
(b) The field lines in the gap will be straight, parallel, and equally spaced — running from the north pole of one magnet to the south pole of the other.
(c) Because the field lines are equally spaced and parallel, the magnetic field has the same strength and direction everywhere between the poles, making it uniform.