3.3.1.2
Polarisation restricts oscillations to a single plane
Wave Types, Polarisation & Stationary Waves — AQA A-Level Physics
Key Definition
Polarisation — When particle oscillations occur in only one of the directions perpendicular to the direction of wave propagation.
- Only transverse waves can be polarised, because they oscillate in any plane perpendicular to the propagation direction.
- Longitudinal waves cannot be polarised because they oscillate parallel to the direction of travel -- there is only one possible oscillation direction.
- Waves can be polarised through a polariser (polarising filter), reflection, refractionThe change in direction of a wave as it passes from one medium to another, caused by a change in wave speed. or scattering.
- A polariser only allows oscillations in one plane to pass through.
Common Mistake
MEDIUM
Students often: Avoid saying that polarisationThe restriction of oscillations of a transverse wave to a single plane. Only transverse waves can be polarised. proves light is a wave.
Instead: PolarisationThe restriction of oscillations of a transverse wave to a single plane. Only transverse waves can be polarised. proves light is a transverse wave. Longitudinal waves are also waves but cannot be polarised.
Instead: PolarisationThe restriction of oscillations of a transverse wave to a single plane. Only transverse waves can be polarised. proves light is a transverse wave. Longitudinal waves are also waves but cannot be polarised.