Section 6 Magnetism and electromagnetism
Notes
Magnetic fields
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Magnetic fields can be described using magnetic field lines which show the direction and strength of the magnetic force.
- At any point in the field of a magnet, the direction of the field line is the direction of the force that would act on a N pole at that point.
- The magnetic field lines around a magnet point from the N pole of the magnet all the way back round to the S pole.
- The magnetic field is strongest where the field lines are closest or most dense.
- If two magnets are placed close together, their magnetic fields will interact. This interaction produces a force that causes the magnets to move if they are free to do so.
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You can show the pattern of magnetic field lines by sprinkling iron filings near the magnet. The iron filings arrange themselves in such a way as to show the magnetic field lines.