Refraction
Refraction of a ray of light by a glass block:
(a) as it entered the block the ray of light would slow down, its wavelength
would decrease and if it entered the block at an angle it would refract, bending towards the
normal (a line at ninety degrees to the block)
(b) it would then travel across the block in a
straight line at a steady speed (less than its speed in air)
(c) as it left the block the ray of
light would speed up to the same speed that it had before it entered the block, its wavelength
would increase and if it left the block at an angle it would refract, bending away the normal so
that it was travelling in the same direction as it was before it entered the
block but shifted
sideways
