04 - Refraction

The bending of light as it passes from one medium to another

*When light travels from a rarer
to a denser medium it is
refracted towards the normal

When light travels from a
denser to a rarer medium it is
refracted away from the

1) The incident ray, the normal and the refracted ray all lie in the same plane.

2) The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant .

i.e. n = Sin i ÷ Sin r , where n is a constant

The Refractive Index of a Medium is the ratio of the sine of the angle of incidence to the sine of the angle of refraction when light travels from a vacuum into that medium.

(if substance, medium= substance)

The refractive index between two media is the ratio of the sine of the angle of incidence to the sine of the angle of refraction when light travels from one of those media into the other.

When light travels from a denser to a rarer medium the angle of incidence whose corresponding angle of refraction is 90° is called the critical angle for those two media.

Occurs when the angle of incidence in the denser medium exceeds the critical angle and all the light is reflected back into the medium.

A very thin transparent rod through which light can
travel by total internal reflection