Snell’s Law- Practice


1) The refractive index of diamond is 2.42. How fast does light travel through diamond?

2) A ray of light travels from a liquid (n=1.42) with a speed of 2.11 × 108 m/s into flint glass (n=1.62). Calculate the speed of the light in flint glass:

3) A ray of light in water (n=1.33) strikes glass (n=1.52) at an incident angle of 30° to the normal. Calculate the angle of refraction:

4) Use the diagram below to calculate the angle of refraction:


5) A light ray travelling through quartz (n=1.46) is incident on a second medium at an angle of 15°. The angle of refraction is 18°. Calculate the refractive index of the second medium:

Quick Answers:

1) v = 1.24 × 10m/s

2) v= 1.85 × 10m/s

3) θ= 25.9°

4) θ= 28.0°

5) n= 1.22 

Worked Answers: