1) As used in the laws of reflection and refraction, what is the definition of the "normal" direction?
2) The refraction index of water is 1.33. When a ray of light incident from water toward air at an incident angle of 30 degrees from the normal, what is the angle of refracted beam in the air from the normal? The refraction index of air is approximately 1.00.
3) The index of refraction of benzene (a chemical, you can find the chemical structure of benzene using Google) is 1.80. The critical angle for total internal reflection, at a benzene-air interface, is about:
A. 56°
B. 47°
C. 34°
D. 22°
E. 18°