SAT Subject Physics Practice Question 511: Answer and Explanation
12. A light ray passes from a material of low refractive index to one of high refractive index. Which of the pairs of quantities listed below describes the light ray as it strikes and passes through the interface between the two materials? Match the descriptions below with the statement that best describes the situation.
A part of the light ray remains inside the low refractive index material.
A. The angle of refraction is larger than the angle of incidence.
B. The angle of refraction is equal to the angle of incidence.
C. The angle of reflection is larger than the angle of incidence.
D. The angle of reflection is smaller than the angle of incidence.
E. The angle of incidence equals the angle of reflection.
Correct Answer: E
The correct answer is (E). When the light is incident to the surface of the second material, a small amount of reflection occurs even though most of the light passes through the surface interface and into the second substance. This means the law of reflection is in effect for the reflected part of the light ray, the angle of reflection equals the angle of incidence.