Waves: Refraction
1. A straight glass rod appears to bend when placed in a beaker of water, as shown in the diagram below.
1.
2.
3.
4.
What is the best explanation for this phenomenon?
The water is warmer than the air.
Light travels faster in water than in air.
Light is reflected at the air-water interface.
Light is refracted as it crosses the air-water interface.
2. A monochromatic light ray (f=5.09 × 1014 Hz) traveling in air is incident on the surface of a rectangular
block of Lucite (n=1.50).
a) Measure the angle of incidence for the light ray to the nearest degree.
b) Calculate the angle of refraction of the light ray when it enters the Lucite block. {Show all work,
including the equation and substitution with units.]
c) What is the angle of refraction of the light ray as it emerges from the Lucite block back into the air?
3. Which diagram best represents the behavior of a ray of monochromatic light in air incident on a block
of crown glass (n=1.52)?
4. A ray of light (f= 5.09 × 1014 Hz) is incident on the boundary between air and an unknown material X
at an angle of incidence of 55°, as shown. The absolute index of refraction of material X is 1.66.
a) Determine the speed of this ray of light in material X.
b) Calculate the angle of refraction of the ray of light in material X.
c) On the diagram above, use a straightedge and protractor to draw the refracted ray of light in material
X.
Reflection, Refraction, Waves
5. Different colors of light travel at different speeds in a transparent medium. In a vacuum, different colors of light
travel at
a. the same speed.
b. different speeds.
6. A beam of light emerges from water into air at an angle. The beam is bent
a. away from the normal.
b. not at all.
c. 48 degrees upward.
d. 96 degrees upward.
e. towards the normal.
7. Which of the following is a consequence of the refraction of light?
a. rainbows
b. mirages
c. internal reflection
d. all of the above
e. none of the above
8. When seen from an airplane, a rainbow sometimes forms a complete circle. When this happens, the plane's
shadow is
a. in the center of the rainbow. This one-I saw it last time I flew to Vancouver. It was really cool!
b. totally outside the rainbow.
c. in the upper part of the rainbow.
d. Nowhere. There is no shadow.
e. in the lower part of the rainbow.
9. When a virtual image is created in a plane mirror
a. the image is upright.
b. the image is located behind the mirror.
c. reflected rays diverge.
d. all of the above
e. none of the above
10. Diffraction occurs for
a. radio waves.
b. X-rays.
c. light.
d. electron beams.
e. all of the above.
11. Suppose you stand 2 m in front of a plane mirror. How far away
from you is your image?
a. ¼ m.
b. ½ m.
c. 1 m.
d. 2 m.
e. 4 m.
12. The shortest plane mirror in which you can see your entire image
a. is half your height.
b. is twice your height.
c. is equal to your height.
d. cannot be determined.
e. depends on how far the mirror is from you.