Geometric Optics

Light travels at the same speed regardless of the material.

Light maintains its direction regardless of the material.

Light bends due to changes in its speed.

Light's speed increases when entering a denser material.

Glass

Water

Air

Vacuum

$1.0 \times 10^8$ m/s

$1.5 \times 10^8$ m/s

$2.0 \times 10^8$ m/s

$6.0 \times 10^8$ m/s

The angle at which light bends when entering a new medium.

The speed of light in a vacuum.

The ratio of the speed of light in a vacuum to its speed in a medium.

The wavelength of light in a medium.

0.75

1.33

1.75

2.25

It bends towards the normal.

It bends away from the normal.

It does not bend.

It bends parallel to the surface.

19.5°

22.0°

45.0°

50.0°

29.1°

58.7°

40.0°

30.0°

Light must travel from a lower index of refraction to a higher index of refraction.

Light must travel from a higher index of refraction to a lower index of refraction.

The angle of incidence must be zero.

The angle of incidence must be equal to the angle of refraction.

30.0°

41.8°

48.2°

53.1°