reflection and refraction

refraction

the change in direction of waves as the speed of waves change from one medium to another.

what are the laws of reflection?

1- the angle of incidence is equal to the angle of reflection at the point of incidence.

2- the incident ray, reflected ray and normal all lie on the same plane

the image found in a plane mirror is

virrtual

upright

laterally inverted

equal distance behind the object as infront

same size and colour as the object

laws of refraction

the ratio of sine of the angle of incidence to the sine of the angle of refractive is a constant called the refractive index

the incident ray, reflected ray and normal all lie on the same plane.

when light travels from a dense to denser medium

the ray goes toward the normal

when light travels from a dense to less dense medium

the ray travels further away from the normal

conditions for total internal reflection

the ray must approach the 2nd medium from one of greater optical density ie. greater refractive index

the angle of incidence must exceed the critical angle

critical angle

angle of incidence at which the angle refraction = 90

TIR

a phenomenon where light, instead of passing through an interface between two mediums, is reflected back into the original medium