Section A

1a Find the angle of refraction, if the angle of incidence is 60°, and the light is entering glass with a refractive index of 1.50 from air.

sin i / sin r = n sin r = sin i / n Angle r = sin-1(sin 60 / 1.5) = 35.3 °

b If the light enters the glass, with the same angle of incidence, from water, will the angle of refraction be more, the same or less?

The light will bend lass at the interface. The angle of refraction will be greater.

2a Find the critical angle for total internal reflection for glass in air if the refractive index of the glass is 1.50.

sin i / sin r = n sin rc = sin i / n Angle rc = sin-1(1 / 1.5) = 41.8 °

b If the glass is in water, is the critical angle for total internal reflection more or less?

The critical angle will be greater.