310102iA 1 Magnetism, Electromagnetism and Electromagnetic Induction Part A 2017 (TF)

Magnetism

A force that acts at a distance and is caused by a magnetic field.

Permanent Magnet

A magnet that retains its magnetism without the need for an external magnetic field.

Temporary Magnet

A magnet that only exhibits magnetic properties in the presence of an external magnetic field.

Magnetite

A naturally occurring magnetic material that is a relatively weak permanent magnet.

Electromagnet

A type of magnet created by wrapping a wire around a metal core and running an electric current through it.

North-seeking pole (N)

The pole of a magnet that is attracted to the Earth's North magnetic pole.

South-seeking pole (S)

The pole of a magnet that is attracted to the Earth's South magnetic pole.

Magnetic Flux

Magnetic lines of force around a magnet, symbolized by the Greek letter phi (ϕ).

Flux Density

The concentration of lines of flux per unit area, symbolized by B, measured in Teslas (T).

Permeability

The ability of a material to concentrate magnetic lines of flux, symbolized by the Greek letter µ (mu).

Reluctance

The opposition to the magnetic flow within a specific path, symbolized by R.

Residual Magnetism

The remaining magnetic effect that persists after the magnetizing force is removed.

Saturation

A condition where all magnetic domains are aligned and no further magnetizing force will increase magnetism.

Coercivity

The measure of a material's ability to withstand an external magnetic field without becoming demagnetized.

Compass

An instrument that uses a magnetized needle to indicate the direction of the Earth's magnetic field.

Cutting a Magnet

A property of magnets where cutting them results in each piece having both N and S poles.

B - H Curve

A graphical representation showing the relationship between magnetic flux density (B) and magnetizing force (H).