A ray of light is incident on a glass/air interface from the glass side. The ray is incident at a 30-degree angle.

1) If this is the minimum angle for which we observe Total Internal Reflection, find the index of refraction 'n' of the glass AND the speed of light in the medium (you may give the speed as a multiple of 'c'.)

2) Assume now the ray is instead incident on the glass/air interface from the AIR side. The ray is again incident at a 30-degree angle.

Find the angle of refraction.

If the ray has a frequency of 640 Hz, what is the wavelength in the air? In the glass?

3) Draw a diagram showing the following for question 2

The interface and normal planes

The incident ray, reflected and refracted rays

(It is helpful to also draw a ray within the glass as a dotted line, parallel to the incident ray. This shows the 'refracted' ray if n1=n2.)

The incident, reflected, and refracted angles