Chapter 17: Reflection and Refraction Practice Test
 1. What is dispersion?
 a. the combining of colored light into white light b. the reflection of colored light c. the separation of light into its spectrum d. the refraction of light
 2. Because of refraction, the Sun actually sets __________ we see it disappear.
 a. hours before b. after c. at the same time as d. before
 3. Why would it be impossible to have optical fibers filled with a vacuum?
 a. because optical fibers must use glass b. there is nothing for light to travel through c. because a vacuum is too optically dense d. there is nothing less optically dense than a vacuum
 4. The line perpendicular to the reflective surface is the __________.
 a. line of refraction b. line of reflection c. normal d. line of incidence
 5. What does Snell's law compare?
 a. the cosines of the refracted angles b. the sines of the refracted angles c. the reflective nature of materials d. the density of the materials
 6. If a substance has a critical angle of 50°, what happens to the light from an incident angle hitting the boundary at 30°?
 a. it is refracted b. it is reflected c. it is diffused d. it is stopped
 7. In relation to a rainbow that you are looking at, where is the Sun?
 a. directly overhead b. in front of you c. in the center of the rainbow d. behind you
 8. A beam of light travels through air (n = 1.0003) and strikes an unknown material at an angle of 50.0°. The new angle of refraction is 25.0°. What is the index of refraction of this material?
 a. 0.643 b. 0.709 c. 1.81 d. 1.20
 9. What is the purpose of cladding in an optical fiber?
 a. prevents scattering of light b. reduces refraction c. prevents reflection d. causes total internal reflection
 10. A light ray is traveling through an unknown material when it intersects ethanol (n = 1.36) at an incident angle of 62.0°. If the angle of refraction is 46.4°, what is the index of refraction of the unknown material?
 a. 2.00 b. 1.12 c. 0.985 d. 1.66