Refraction occurs at a boundary The speed of light must change
at the boundary The angle of the light ray is measured from the
normal, as was the case with reflection
Slide 3
If the speed slows across the boundary, the refracted angle
will be smaller the light ray will bend toward the normal. If the
speed increases across the boundary, the light ray will bend away
from the normal
Slide 4
Refraction is the bending of light when it enters from one
transparent medium into another. It is caused by the different
speeds of light in different media. The greater the optical density
of the medium, the slower the speed of light.
Slide 5
Slide 6
Incident ray Refracted ray Emergent ray Angle of incidence
Angle of refraction normal Angle of emergence
Slide 7
Laws of Refraction 1.The incident ray, the refracted ray and
the normal all lie in the same plane. 2.For two particular media,
the ratio of the sine of the angle of incidence to the sine of the
angle of refraction is a constant. (Snells Law )
Slide 8
Refractive Index When light passes from vacuum (or air) into a
given medium (eg. water), the constant ratio is known as the
refractive index, n, for that medium. Angle of incidence Angle of
refraction
Slide 9
MediumIndex of refraction = n Vacuum 1 Water 1.33 Lucite 1.5
diamond 2.4
Slide 10
From more dense to less dense
Slide 11
Swimming pool and ponds appear shallower than it really is.
Object is at a deeper depth than where it appears to be. Bent
objects in liquids
Slide 12
Notice that the fish appears more shallow to the person.
Slide 13
On a hot summer day, as you drive down a road, you see what
appears to be the reflection of an oncoming car in a pool of water.
The pool, however, disappears as you approach it. Mirage s
Refraction of Light
Slide 14
Mirages The mirage is the result of the Sun heating the road.
The hot road heats the air above it and produces a thermal layering
of air that causes light traveling toward the road to gradually
bend upward. This makes the light appear to be coming from a
reflection in a pool.