Skip to content
Dabour HubLEARN · PRACTICE · EXPLORESign inStudent

8.2Chapter 8: Magnetism and Electromagnets

Magnetic fields — Alhussan Physics - Stage 8 Revision Notes & Topical Questions

5 min read 7 parts Lesson 2 of 6 1 quiz

📚 Alhussan Physics - Stage 8 Hub / Topical Revision
🩺
100% Curriculum Specification Match Lesson Doctor Verified
The only platform with 100% curriculum specification match and verified interactive question banks.
0%read
Lesson summary

Physics 8.2 Magnetic fields — Plotting Field Lines with Compasses and Iron Filings — Alhussan International Academy — Physics (Stages 7–9) notes: Define a magnetic field and describe how to find its shape around a bar magnet.Magnetic field = the region around a magnet where magne…

  • Ferrofluid
  • In a field
  • Two magnets
  • Plotting compass
  • Representation
  • No crossing

Part 1 of 5What a magnetic field is

Magnetic field
Magnetic field the region around a magnet where magnetic materials experience a force.
Steel pin
  • A pin placed near a magnet moves because the magnet exerts a force on it.
Ferrofluid
  • A special magnetic liquid that forms patterns because it is in a magnetic field.
Invisible
  • We cannot see the field, only its effect on magnets and magnetic materials.

Part 2 of 5Iron filings

Iron filings
Iron filings very small flakes of iron.
In a field
  • They become magnetised and line up like paper clips, showing the shape of the field.
Two magnets
  • Filings can also show the pattern around two magnets that attract or repel.

Part 3 of 5Plotting compass method

1
Place a bar magnet on paper and put a plotting compass near one pole.
2
Mark a pencil dot at each end of the compass needle.
3
Move the compass so that one end of the needle is at the last dot and mark the new dot.
4
Repeat until the compass reaches the other pole.
5
Join the dots to give one field line, and repeat from other starting points.
  • Plotting compass
    • A very small compass whose needle lines up with the magnetic field.

Part 4 of 5Reading field lines

Representation
  • Field lines show the general shape of the field, which exists all around the magnet in three dimensions.
Direction
  • Arrows point from the north pole towards the south pole.
Strength
  • The field is stronger where the lines are closer together, so it is strongest at the poles.
No crossing
  • Field lines never cross.

Part 5 of 5Two magnets together

Interaction
  • The field of one magnet exerts a force on the other, so magnets attract or repel.
Straightening
  • Magnets also move so as to straighten the field lines.
Neutral point
Neutral point a point where the magnetic fields of two magnets cancel out, giving zero field.
ArrangementField linesForce
N facing SJoin up straight across the gapAttraction
N facing NBend away from each otherRepulsion

Key terms

TermMeaning
Magnetic fieldThe region where magnetic materials experience a force.
Field lineA line showing the direction of the magnetic field.
Plotting compassA very small compass used to find field direction.
Neutral pointA point where two magnetic fields cancel out.
FerrofluidA magnetic liquid that forms patterns in a field.

Avoid these mistakes

1
Thinking field lines are real objects — they only represent the field.
2
Thinking the field exists only where lines are drawn — it is all around the magnet.
3
Thinking field lines point from south to north — they point from north to south.
4
Thinking iron filings make the field — they only show it.

?What do you want to solve now?

Practice questionsTraining questions with instant feedback - not an exam.

Last updated: