Creating a uniform magnetic field
3 marks · EasyDescribe an experiment you could carry out to show the magnetic field pattern around a single bar magnet.
What would you observe in your experiment to indicate the positions of the field lines?
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.
Show answer
(a) Place a bar magnet under a piece of paper or a plastic sheet. Sprinkle iron filings evenly onto the paper. Gently tap the paper so the filings align along the field lines. · must show bar magnet placed under sheet, use of iron filings, tapping or shaking to reveal lines
(b) The iron filings line up in curved patterns showing the shape of the magnetic field lines. · must show filings align along field lines
Common mistakes: Not mentioning the use of iron filings or compasses; Not describing the observation
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · References correct placement of magnet and paper/sheet
M2 (a) · 1 mark · Describes use of iron filings (or compasses) and tapping/shaking
B1 (b) · 1 mark · Mentions that filings arrange themselves in patterns that show/trace field lines
Worked solution
a) Place a bar magnet under a sheet of paper. Sprinkle iron filings onto the sheet. Tap the paper gently so the filings align with the magnetic field.
b) You will observe the iron filings making curved patterns from the north to the south pole. These show the shape of the magnetic field lines.