Laser light is passed through a rod made out of a material with an index of refraction of 1.63, a length L = 45.0 cm, and square cross section of length h = 3.00 mm on a side as shown in the figure. If the light enters at the center of the rod with an angle of incidence in air of θ1 = 50.9°, determine the number of total internal reflections before it emerges from the opposite end of the rod.
Please show your work, and if you could explain what equations you used, it'd be greatly appreciated.