DEFINITION LIST: WAVES
Normal – the imaginary line perpendicular to the surface between two
different optical media.
Medium – The substance or material that carries a wave.
Laws of reflection – the incident ray, refracted ray and normal are all in the
same plane. The angle of incidence is equal to the angle of reflection.
Refraction – the bending of light as it moves from one medium to another
medium with a different optical density.
Optical density – a measure of the speed of light or other electromagnetic
waves through a medium.
Refractive index – the ratio of the speed of light in air to the speed of light
through another medium.
Snell’s Law – the ration of the sine’s of the angles of incidence and refraction
of a wave are constant when it passes between two given media.
Critical angle – the angle of incidence for which the angle of refraction is 90°.
Total internal reflection – The reflection of light on the inside surface of a
medium when light is travelling towards a medium of lower optical density and
the angle of incidence is larger than the critical angle
Interference – A phenomenon in which two waves superimpose to form a
resultant wave of greater or lower amplitude
Diffraction – The ability of a wave to spread out in wavefronts as they pass
through a small aperture or around a sharp edge OR the bending of a wave as
it passes around the edges of an object.
Huygen’s priniciple – Every point on a wave may be considered as a source of
secondary wavelets which spread out in all directions at the same speed as the
wave itself.