Magnetic fields
4 marks · NormalA student investigates the magnetic field around a bar magnet using iron filings and then plotting compasses.
Describe how iron filings can be used to show the shape of the magnetic field around a bar magnet.
Explain how plotting compasses can show the direction of the magnetic field around the magnet.
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) Sprinkle iron filings on paper over the bar magnet; gently tap so filings align with field lines, showing the field's shape. · must show iron filings sprinkled, filings line up along field lines, shape of field shown
(b) Place plotting compasses near the magnet; the compass needles point along the field, showing the direction at each point. · must show compasses placed near magnet, needles show direction, points north to south
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Iron filings are sprinkled on paper/card above magnet
A1 (a) · 1 mark · Iron filings align along field lines (field pattern seen by tapping paper gently)
M2 (b) · 1 mark · Compasses placed on paper near bar magnet
A2 (b) · 1 mark · Needle points along field at each position (shows direction from north to south pole)
Worked solution
a) Place a bar magnet under a sheet of paper, sprinkle iron filings on top, and gently tap. The filings align along magnetic field lines, revealing the field shape.
b) Place plotting compasses around the magnet. At each point, the compass needle aligns with the magnetic field direction, pointing from the magnet's north pole to south pole.