Polarisation

Waves are referred to as polarised when they oscillate in one plane only. Most naturally occurring electromagnetic waves are unpolarised. In order to polarise a wave, a polarising filter can be used. This filter only allows waves of a particular orientation to pass through.

Polarisation can be used with radio transmission to prevent interference. Each broadcaster could polarise their waves at different angles, so that they do not interfere with one another. Polarising filters can also be used in photography, to reduce glare and reflections.

Transverse waves can be partially polarised when they reflect off a surface. This means that most of the oscillations occur in one plane, but not all of them.