Physics 5 Flashcards
Refraction
The bending of light due to a change in the medium thee which light is travelling
Optical Density
The density of a medium in which light can travel through optical density is a ratio of the speed of light and the speed of light in “dense” material
n= c/v
n=c/v
n=optical density
c= speed of light
Towards and away from normal
When travelling from less to more dense material, light bends towards the normal
When light travels from more to less dense light bends away from
the normal
Snells Law
- a ray of light bends in such a way that the ratio of the sine of the angle of incidence to the sine of the angle of retraction is a constant
n1sinθ1 = n2 sinθ2
Laws of Refraction
I. The ratio of the sine of the angle of the incidence to the sine of the angle of refraction is a constant. (snells lawl)
2. The incident ray and the retracted ray are on opposite sides of the normal at the point of incidence
13. All three are on the same plane. (The normal, incident and refracted rays.)
Absolute Index of Retraction
comparing (for example) light traveling from air (or a vacuum) to
some other medium. This is termed Absolute Index of refraction
Relative Index of Refraction
when light travels between two materials with different indices of refraction, the ratio of their absolute indices of refraction is reffered to as the relative index of refraction.
aNb= Nb/Na
Critical Angle
The critical cingle is the incidence angle where the refracted ray NO LONGER leaves medium 1, but travels on the boundory between medium 1 and medium 2
The refracted angle is 90°
Sine of 90° is always equal to 1
Total Internal Reflection
occurs at any angle greater than the critical angle. TIR is ONLY possible if light is travelling through MORE dense material (higher refractive index) to a less dense material (lower refractive index)
A higher index of refraction will result in a smaller critical angle
Waves
look at pictures in notes
