The monochromatic light of the wavelength 700 nm is shined at the surface of the unknown material.
The thickness of the material is h = 1 cm, and the light leaves the material displaced by a = 2 mm in the
horizontal direction (distance between the horizontal positions when it enters and leaves the material)

a) If the angle of reflection (measured from the normal) for the incident light is θi = 45◦ what is the angle (also measured from the normal) of the reflected light θr?

b) What is the refraction index of the material?

c) If you now put the light source in the material what would be the minimum angle θc for which the total reflection occurs?