Conceptual Physics
Reflection and Refraction
Practice Test
1. What is meant by a virtual image? Where does the image produced by a mirror appear?
(check notes)
2. a. What are the characteristics of an image produced in a place mirror? (check notes)
b. The man below is gazing at himself in a mirror. Sketch his reflection (image). Compare the height
and distance from the mirror of the man and his image. Label the real space and the virtual space. (He
should be drawn behind the mirror, facing the real man, straight arm in front, bent arm in back. Same distance behind mirror as man is from front of
mirror, same size as man. Real space is where man is, virtual space is behind the mirror.)
3a. A red flashlight is pointed toward the surface of a calm lake.
a. What can happen to the light at the air/water interface?
b. What is the velocity of the light in the air?
c. What happens velocity of the light as it moves into the water?
d. What happens to the wavelength of the light as it moves into the water?
e. What happens to the frequency of the laser as it moves into the water?
f. Sketch a diagram of the flashlight ray as it hits the air water interface at an angle of 42o. Draw
the reflected ray. Draw the refracted ray in the water at an angle of 30o. Label the incident ray,
the reflected ray the refracted ray, the angle of incidence, angle of reflection and angle of
refraction.
4. Light travels slowest in:
(a) water
(b) air
(c) corn oil
(d) quartz
5. In the spaces below, indicate how each of the wave characteristics listed below is affected when
yellow light is transmitted from air into glass:
(a) the light’s wavelength
(b) the light’s frequency
(c) the light’s speed
6. A ray of light moves from coconut oil to water as shown in the diagram to the right. The index of
refraction of the coconut oil is 1.7 and the index of refraction for the water is 1.33.
a. Why does the ray bend as it moves from the oil into the water?
b. What is the name of this phenomenon?
c. On the diagram, label the normal. What is the angle of incidence
(θ1) ? What is the angle of refraction? (θ2)
d. In which substance does the light travel faster?
e. Find the speed of light in the coconut oil.
3.a. the light can reflect off the surface of the lake, refract (be transmitted through the water) or be absorbed by the water. b. 3 x 10 8 m/s. c. it slows
down. d. it gets smaller. e. it remains the same. f. draw diagram and label. Use notes as a reference. 4. the substance that has the highest index of
refraction (look on reference table). 5a. decreases. b. stays the same. c. decreases. 6a. the end of the wave that hits the water first speed up while the
other end of the wave front is still moving slowly in the coconut oil. b. refraction. c. normal is dotted line that is perpendicular to the coconut oil-water
interface, angle of incidence is 35o. angle of refraction is 47o. d. in the water because water has a lower index of refraction than the coconut oil.
e. use n = c/v n = 1.7, c = 3E8 m/s; v = 1.76E8 m/s.
7.
An incident ray hits the mirror with an angle of incidence of 57o. Draw the incident and the
reflected rays. Label the incident ray, the reflected ray the angle of incidence and the angle of
reflection. (Draw diagram and label according to notes)
mirror surface
8. A laser shines into a lucite block from the left as shown below. What is the angle of incidence? The
laser ray refracts across the air/lucite interface at an angle of 25o. The ray hits the next interface at an
angle of 65o and is internally reflected. Draw the internally reflected ray on the diagram below.
8. angle of incidence is 38o , draw normal on top of block, measure 65o to the right of the normal and draw the ray to the next interface. For reflection, the
angle of incidence (as measured from the normal) is equal to the angle of reflection (as measured from the normal.)
11. What is the “normal” and how is it drawn? What is the law of reflection (with respect to the angles
of incidence and reflection)? How is the angle of incidence measured? How is the angle of reflection
measured? How is the angle of refraction measured? (see notes for answers.)
12. a. Draw the A as it would appear in the mirror. How does the image compare to the object?
(compare size, distance from the mirror, where it appears and how it appears).
b. Where would a person have to stand in order to see the snake in the mirror?
real space
mirror surface
virtual space