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MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 15: REFLECTION AND REFRACTION
WORKSHEET SOLUTIONS
1. Light in air enters a diamond (n = 2.42) at an angle of incidence of 30.0o. What is the angle of
refraction inside the diamond?
1A.
(1) n = sin1 / sin2
(2) sin2 = sin1 / n
(3) sin2 = sin 30o / 2.42
(4) sin2 = 0.2066
(5) 2 = arcsin2 = 11.9o
2. An underwater scuba diver sees the sun at an apparent angle of 35.0o from the vertical. How far is
the sun above the horizon? (nwater = 1.33)
2A.
(1) n = sin2 / sin1
(2) (n)(sin1) = sin2
(3) (1.33)(sin 35o) = sin2
(4) sin2 = 0.7629
(5) 2 = arcsin2 = 49.7o
3. Dispersion occurs when:
(A) some materials bend light more than other materials
(B) a material slows down some wavelengths more than others
(C) a material changes some frequencies more than others
(D) light has different speeds in different materials
(E) a material changes the color of incoming light
4. If the velocity of light through an unknown liquid is measured at 1.85 x 108 m/s, what is the index of
refraction of this liquid?
4A.
(1) n = c / v
(2) n = 3.00 x 108 m/s / 1.85 x 108 m/s
(3) n = 1.62
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
5. If the critical angle for internal reflection inside a certain transparent material is found to be 56.0o,
what is the index of refraction of the material? (Air is outside the material).
5A.
(1) sin c = n2 / n1
(2) n1 = n2 / sinc
(3) n1 = 1.00 / sin 56o
(4) n1 = 1.21
6. Which of the following describes what will happen to a light ray incident on an air-to-glass boundary
at less than the critical angle?
(A) total reflection
(B) total transmission
(C) total dispersion
(D) partial reflection, total transmission
(E) partial reflection, partial transmission
6A.
7. A beam of light in air is incident at an angle of 35.0o to the surface of a rectangular block of clear
plastic (n = 1.49). The light beam first passes through the block and re-emerges from the opposite side
into air at what angle to the surface?
Example 7. Diagram
7A. 35o
8. A beam of light in air is incident on the surface of a rectangular block of clear plastic
(n = 1.49). If the velocity of the beam before it enters the plastic is 3.00 x 108 m/s, what is its velocity
after emerging from the block?
8A. 3.00 x 108 m/s
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
9. A ray of light in air is incident on an air-to-glass boundary at an angle of 41.5o with the normal. If
the index of refraction of the glass is 1.47, what is the angle of the refracted ray within the glass with
respect to the normal?
9A.
(1) n = sin1 / sin2
(2) sin2 = sin1 / n
(3) sin2 = sin 41.5o / 1.47
(4) sin2 = 0.4508
(5) 2 = arcsin2 = 26.8o
10. A light in air is incident on an air-to-glass boundary at an angle of 45.0o and is refracted in the glass
at an angle of 30.0o with the normal. What is the index of refraction of the glass?
10A.
(1) n = sin1 / sin2
(2) n = sin 45o / sin 30o
(3) n = 0.7071 / 0.5
(4) n = 1.41
11. A laser beam, incident at 30 degrees onto the surface of a block of glass, is partially reflected and
partially transmitted (with refraction) at the block’s upper surface. The index of refraction of the glass
is 1.5.
Example 11. Diagram
11a. What is the speed of light in the glass expressed as a fraction of c?
A.
(1) n = c / v
(2) v = c / n
(3) v = (1 c) / (1.5)
(4) v = 0.67 c
11b. Is the angle of refraction greater than, less than, or equal to 30 degrees?
A. less than
11c. Calculate the angle of refraction in degrees.
A.
(1) n1sin1 = n2sin2
(2) sin2 = (n1)(sin1) / (n2)
(3) sin2 = (1.0)(sin30o) / (1.5)
(4) sin2 = 0.333
(5) 2 = arcsin2 = 19.5o
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
11d. What is the angle the reflected beam makes with the normal?
A. 30 degrees. The angle of reflection = the angle of incidence.
12. A beam of light in water strikes a boundary with air. The index of refraction of water is 1.33.
12a. If the angle of incidence is 41 degrees what is the angle of refraction?
A.
(1) n1 sin 1 = n2 sin 2
(2) sin2 = (n1)(sin 1) / (n2)
(3) sin2 = (1.33)(sin 41o) / (1.00)
(4) sin2 = 0.8726
(5) 2 = arcsin2 = 60.8o
12b. Calculate the critical angle for these rays.
A.
(1) n1sin1 = n2sin2
(2) sin1 = (n2)(sin2) / (n1)
(3) sin1 = (1.00)(sin 90o) / (1.33)
(4) sin1 = 0.752
(5) 1 = arcsin1 = 48.8o
12c. If the angle of incidence is 61 degrees what happens to the light at the boundary?
A. It is totally reflected.
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 15: REFLECTION AND REFRACTION
QUIZ SOLUTIONS
1. Light in air enters a diamond (n = 2.42) at an angle of incidence of 41.2o. What is the angle of
refraction inside the diamond?
1A.
(1) n = sin1 / sin2
(2) sin2 = sin1 / n
(3) sin2 = sin 41.2o / 2.42
(4) sin2 = 0.2722
(5) 2 = arcsin2 = 15.8o
2. If the velocity of light through an unknown liquid is measured at 1.97 x 108 m/s, what is the index of
refraction of this liquid? (c = 3.00 x 108 m/s)
2A.
(1) n = c / v
(2) n = 3.0 x 108 m/s / 1.97 x 108 m/s
(3) n = 1.52
3. If the critical angle for internal reflection inside a certain transparent material is found to be 46.5o,
what is the index of refraction of the material? (Air is outside the material).
3A.
(1) sinc = n2 / n1
(2) n1 = n2 / sinc
(3) n1 = 1.00 / sin 46.5o
(4) n1 = 1.38
4. A ray of light in air is incident on an air-to-glass boundary at an angle of 12.8o with the normal. If
the index of refraction of the glass is 1.87, what is the angle of the refracted ray within the glass with
respect to the normal?
4A.
(1) n = sin1 / sin2
(2) sin2 = sin1 / n
(3) sin2 = sin 12.8o / 1.87
(4) sin2 = 0.1185
(5) 2 = arcsin2 = 6.8o
5. A light in air is incident on an air-to-glass boundary at an angle of 48.7o and is refracted in the glass
at an angle of 27.5o with the normal. What is the index of refraction of the glass?
5A.
(1) n = sin 1 / sin 2
(2) n = sin 48.7o / sin 27.5o
(3) n = 1.63
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
6. A laser beam, incident at 35 degrees to the normal on the surface of a glass block, is partially
reflected and partially transmitted (with refraction) at the block’s upper surface. The index of refraction
of the glass is 1.6.
6a. The speed of light in a vacuum is c = 3.0 x 108 m/s. What is the speed of light in this glass
expressed as a fraction of c?
A.
(1) n = c/v
(2) v = c/n
(3) v = (1 c) / (1.6)
(4) v = 0.625 c
6b. Is the angle of refraction greater than, less than, or equal to 35 degrees?
A. less than
6c.
A.
(1)
(2)
(3)
(4)
(5)
Calculate the angle of refraction in degrees.
n1sin1 = n2sin2
sin2 = (n1)(sin1) / (n2)
sin2 = (1.0)(sin35o) / (1.6)
sin2 = 0.3585
2 = arcsin2 = 21.0o
6d. What is the angle the reflected beam makes with the normal?
A. 35 degrees.  = ’
7. A beam of light in water strikes a boundary with air. The index of refraction of water is 1.33.
7a.
A.
(1)
(2)
(3)
(4)
(5)
If the angle of incidence is 32.7 degrees what is the angle of refraction?
n1sin1 = n2sin2
sin2 = (n1)(sin1) / (n2)
sin2 = (1.33)(sin 32.7o) / (1.00)
sin2 = 0.7185
2 = arcsin2 = 43.9o
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MR. SURRETTE
7b.
A.
(1)
(2)
(3)
(4)
(5)
VAN NUYS HIGH SCHOOL
Calculate the critical angle for these rays.
n1 sin 1 = n2sin2
sin 1 = (n2)(sin 2) / (n1)
sin 1 = (1.00)(sin 90o) / (1.33)
sin 1 = 0.752
1 = arcsin1 = 48.8o
7c. If the angle of incidence is 10 degrees, what happens to the light at the boundary?
A. refracted outside to the air.
8. Dispersion occurs when:
8A. a material slows down some wavelengths more than others
9. A beam of light in an unknown medium is incident on the surface of a rectangular block of clear
plastic (n = 1.49) If the velocity of the beam before it enters the plastic is 1.54 x 108 m/s, what is its
velocity after emerging from the block?
9A. 1.54 x 108 m/s
10. A beam of light in air is incident at an angle of 40.0o to the surface of a rectangular block of clear
plastic ( n = 1.49). The light beam first passes through the block and re-emerges from the opposite side
into air at what angle to the normal to that surface?
10A. 40.0o
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