Physics · 4.1 Magnetism · Field patterns · Paper 6
Magnetic Fields. Plot it.
Plot the field around a bar magnet (or between two), and around a current-carrying wire or solenoid. Drag a plotting compass to see how it lines up with the field. Field lines run N → S and never cross.
0625 Topic 4.1 — Magnetism
4.5.1 — Field around a wire / coil
Variables
1.0
—
What the field shows
Field direction
N pole → S pole
Line spacing
closer = stronger
Right-hand rules
Wire: grip with right hand, thumb along current, fingers curl in field direction.
Field lines never cross, are closest where the field is strongest, and run from N to S outside a magnet.
📋 Method (Cambridge — plotting with a compass)
- Place the magnet on paper and draw round it.
- Put a plotting compass near the N pole; mark dots at the ends of the needle.
- Move the compass so its tail sits on the previous dot; mark the new head. Repeat across to the S pole.
- Join the dots into a smooth field line with an arrow N → S. Repeat from several start points.
Iron filings give a quick picture of the whole pattern but no direction — the compass gives direction.
🎯 Syllabus reference (0625)
- 4.1 Magnetism — describe the field pattern of a bar magnet and between two magnets; state that like poles repel and unlike attract; describe plotting fields with a compass and iron filings.
- 4.5.1 Magnetic effect of a current — describe the field around a straight current-carrying wire and a solenoid; state how to reverse and strengthen the field.