The diagram shows the passage of a ray of light from air into a substance X. The index of refraction of X is:
A) 0.53
B) 0.88
C) 1.9
D) 2.2
E) 3.0

Question

The diagram shows the passage of a ray of light from air into a substance X. The index of refraction of X is: 
A) 0.53 
B) 0.88 
C) 1.9 
D) 2.2 
E) 3.0

Quizplus · Accepted Answer

The angle of incidence is larger than the angle of refraction, which means that the ray of light is bending toward the normal as it passes into substance X. Therefore, the index of refraction of substance X must be greater than 1.0. Choice A and B are less than 1.0, so they are not possible. Choice E is too large and unlikely for most materials, leaving choices C and D. The angle of refraction is quite small, so we need a large index of refraction to explain the bending that occurs. Therefore, the best choice is C, 1.9.

The Diagram Shows the Passage of a Ray of Light