Total Internal Reflection Practice Test

A scuba diver is wearing a head lamp and looking up at the surface of the water. If the minimum angle to the vertical resulting in total internal reflection is , what is the index of refraction of the water?

A ray of light makes a transition from a sample of benzene to water. What is the minimum angle the light must make with respect the normal in order for the light to be completely reflected back into the sample of benzene?

The index of refraction for water is 1.33 and for benzene is 1.50.