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Magnetic field, Meaning (SPM Physics)

The region around a magnet or current-carrying conductor in which a magnetic force can be detected.

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EnglishMagnetic field
Bahasa MelayuMedan magnet
中文磁场

Definition

The region around a magnet or current-carrying conductor in which a magnetic force can be detected.

Electromagnetism

In exam terms

A magnetic field is the region around a magnet or a current-carrying conductor in which a magnetic force can be detected. It is represented by magnetic field lines that point from the north pole to the south pole outside a magnet; where the lines are closer together the field is stronger.

Around a straight current-carrying wire the field lines form concentric circles, whose direction is given by the right-hand grip rule.

Example of correct use: iron filings sprinkled around a bar magnet line up along the magnetic field, revealing its pattern.

Do not confuse it with…

Do not confuse a magnetic field with an electric field. A magnetic field is produced by magnets or moving charges and acts on other magnets and moving charges; an electric field is produced by charges and acts on any charge, whether moving or at rest.

The two are distinct even though both are represented by field lines.

In Paper 2 you may be asked to sketch the field pattern of a bar magnet or a current-carrying wire, or to state how the pattern shows the direction and relative strength of the field.

Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)

Frequently asked questions

Which way do magnetic field lines point?
Outside a magnet, field lines point from the north pole to the south pole. They never cross, and closer lines show a stronger field.
How do you find the field direction around a wire?
Use the right-hand grip rule: grip the wire with your right hand, thumb pointing in the direction of the current, and your curled fingers show the direction of the circular field lines.
How is a magnetic field different from an electric field?
A magnetic field acts on magnets and moving charges and is made by magnets or currents; an electric field acts on any charge and is made by charges themselves.

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