Magnetic field lines of a bar magnet
Outside N→S; denser near poles; never intersect.
Step 1 — Study the figure
Cover the label key on the image, name each numbered part, then check the explanations below.
Step 2 — Diagram details for students
What this diagram shows
Magnetic field lines show the direction and relative strength of a magnetic field around a bar magnet. Outside, lines go from north to south, are denser near poles, and never intersect. Inside the magnet they continue to form closed loops.
Numbered parts — mark & remember
Match each number on the figure with the meaning below. Say the function aloud once.
1 North pole
Field lines emerge from the north pole outside the magnet. A compass north pole points roughly in the local field direction. Mark N clearly on diagrams.
2 South pole
Outside the magnet, field lines enter the south pole. Poles always exist in pairs in ordinary magnets. Breaking a magnet still gives new N–S pairs.
3 Field line path
Lines are continuous closed curves from N to S outside and S to N inside. They never cross because field direction at a point must be unique. Closer spacing means stronger field.
4 Dense near poles
Near the poles, lines are crowded, showing stronger magnetic field. Farther away, lines spread and field weakens. Use density as a qualitative strength clue in answers.
How to read this figure
- Outside direction is N → S.
- No intersection of lines.
- Density ∝ strength.
Redraw for board marks
- Draw bar magnet with N and S.
- Sketch several loops from N to S outside.
- Pack lines closer near the poles.
Board answer tip: Draw labelled bar-magnet field and list three properties of field lines.
Exam tips — don’t lose marks
- Never draw crossing field lines.
- State closed-curve nature if asked for properties.
- Compass aligns with field direction.