Reflection and Refraction
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1. A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 25° with the normal. Find the angle of the
ray reflected off the glass surface with respect to the normal.
a. 56°
c. 39°
b. 46°
d. 25°
____
2. As the angle of incidence is increased for a ray incident on a reflecting surface, the angle between the incident
and reflected rays ultimately approaches what value?
a. zero
c. 90°
b. 45°
d. 180°
____
3. Which of the following describes what will happen to a light ray incident on an air-to-glass boundary?
a. total reflection
c. partial reflection, partial transmission
b. total transmission
d. partial reflection, total transmission
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4. Light from a 560-nm monochromatic source is incident upon the surface of fused quartz (n = 1.56) at an angle
of 60°. What is the angle of reflection from the surface?
a. 15°
c. 60°
b. 34°
d. 75°
____
5. The lowest possible value for the index of refraction is:
a. 0.
c. 0.707.
b. 1.
d. 3-1/2.
____
6. What is the maximum possible arc that can be subtended by a rainbow? (Consider all possible viewing
geometries).
a. 90°
c. 270°
b. 180°
d. 360°
____
7. Three flat layers of transparent material are stacked upon one another. The top layer has index of refraction
n1, the middle has n2 and the bottom one has n3. If n1 < n2 < n3, at what angle of incidence will a ray of light
traverse the three layers in a single straight line?
a.  i  sin 1 ÊÁË 1 / n 1 ˆ˜¯
c.  i  tan1 ÊÁË n 1  n 2  n 3 ˆ˜¯
b.  i  sin 1 ÊÁÁ 1 / ÊÁË n 1  n 2  n 3 ˆ˜¯ ˆ˜˜
d. There is such an angle, but it is not given.
Ë
¯
____
8. According to the photon energy formula, tripling the frequency of the radiation from a monochromatic source
will change the energy content of the individually radiated photons by what factor?
a. 0.33
c. 1.73
b. 1.0
d. 3.0
____
9. Tripling the wavelength of the radiation from a monochromatic source will change the energy content of the
individually radiated photons by what factor?
a. 0.33
c. 1.73
b. 1.0
d. 3.0
1
____ 10. Photon A has an energy of 2.0  10-19 J. Photon B has 4 times the frequency of Photon A. What is the energy
of Photon B?
a. 0.50  10-19 J
c. 8.0  10-19 J
-19
b. 1.0  10 J
d. 32  10-19 J
____ 11. What is the energy of a photon of frequency 5.00  1014 Hz? (h = 6.626  1034 Js)
a. 3.31  1019 J
c. 1.33  1048 J
b. 3.31  1047 J
d. 1.33  1024 J
____ 12. Helium-neon laser light has a wavelength in air of 632.8 nm. What is the energy of a single photon in the
beam? (h = 6.626  1034 Js and c = 3.00  108 m/s).
a. 3.14  1019 J
c. 7.62  1019 J
19
b. 5.40  10 J
d. 1.15  1018 J
____ 13. Water has an index of refraction of 1.333. What is the speed of light through it? (c = 3.00  108 m/s)
a. 4.00  108 m/s
c. 4.46  108 m/s
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b. 2.25  10 m/s
d. 1.46  108 m/s
____ 14. A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 25° with the normal. Find the angle of the
refracted ray within the glass with respect to the normal.
a. 56°
c. 25°
b. 46°
d. 16°
____ 15. Dez pours carbon tetrachloride (n = 1.46) into a container made of crown glass (n = 1.52). The light ray in
glass incident on the glass-to-liquid boundary makes an angle of 30° with the normal. Find the angle of the
corresponding refracted ray.
a. 55.5°
c. 31.4°
b. 29.4°
d. 19.2°
____ 16. A monochromatic beam of light in air has a wavelength of 589 nm in air. It passes through glass (n = 1.52)
and then through carbon disulfide (n = 1.63). What is its wavelength in the carbon disulfide?
a. 361 nm
c. 895 nm
b. 387.5 nm
d. 960 nm
____ 17. A light ray in air is incident on an air-to-glass boundary at an angle of 30.0° and is refracted in the glass at an
angle of 21.0° with the normal. Find the index of refraction of the glass.
a. 2.13
c. 1.23
b. 1.74
d. 1.40
____ 18. A beam of light in air is incident at an angle of 30° to the surface of a rectangular block of clear plastic (n =
1.46). 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?
a. 42°
c. 30°
b. 23°
d. 59°
____ 19. 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  108 m/s, what is its velocity inside the block?
a. 3.00  108 m/s
c. 2.01  108 m/s
b. 1.93  108 m/s
d. 1.35  108 m/s
2
____ 20. Monochromatic light hits a piece of glass. What happens to the wavelength in the glass as the index of
refraction increases?
a. decreases
c. remains constant
b. increases
d. approaches 3  108 m
____ 21. If the speed of light through an unknown liquid is measured at 1.80  108 m/s, what is the index of refraction
of this liquid? (c = 3.00  108 m/s)
a. 1.80
c. 1.20
b. 1.67
d. 0.600
____ 22. If the wavelength of a monochromatic source is 490 nm in vacuum, what is the wavelength from the same
source when it passes through a liquid where the speed of light is 2.40  108 m/s? (c = 3.00  108 m/s)
a. 671 nm
c. 490 nm
b. 612.5 nm
d. 392 nm
____ 23. What is the angle of incidence on an air-to-glass boundary if the angle of refraction in the glass (n = 1.52) is
25°?
a. 16°
c. 40°
b. 25°
d. 43°
____ 24. A monochromatic light source emits a wavelength of 490 nm in air. When passing through a liquid, the
wavelength reduces to 429 nm. What is the liquid’s index of refraction?
a. 1.26
c. 1.14
b. 1.49
d. 1.33
____ 25. Fused quartz has an index of refraction of 1.56 for light from a 560-nm source. What is the speed of light for
this wavelength within the quartz? (c = 3.00  108 m/s)
a. 1.56  108 m/s
c. 2.19  108 m/s
b. 1.92  108 m/s
d. 4.68  108 m/s
____ 26. If light from a 560-nm monochromatic source in air is incident upon the surface of fused quartz (n = 1.56) at
an angle of 60°, what is the wavelength of the ray refracted within the quartz?
a. 192 nm
c. 560 nm
b. 359 nm
d. 874 nm
____ 27. A ray of light travels from a glass-to-liquid interface at an angle of 35.0°. Indices of refraction for the glass
and liquid are, respectively, 1.52 and 1.63. What is the angle of refraction for the ray moving through the
liquid?
a. 23.2°
c. 38.4°
b. 32.3°
d. 46.0°
____ 28. A ray of light is incident on a liquid-to-glass interface at an angle of 35°. Indices of refraction for the liquid
and glass are, respectively, 1.63 and 1.52. What is the angle of refraction for the ray moving through the
glass?
a. 23°
c. 38°
b. 30°
d. 46°
3
____ 29. A light ray passes from air through a thin plastic slab (n = 1.3) with parallel sides. If the ray in air makes an
angle of 45° with the normal after leaving the slab, what is the angle of incidence for the ray in air as it
impinges upon the other side of the slab?
a. 33°
c. 67°
b. 45°
d. 58.5°
____ 30. An oil film floats on a water surface. The indices of refraction for water and oil, respectively, are 1.333 and
1.466. If a ray of light is incident on the air-to-oil surface at an angle of 37.0° with the normal, what is the
incident angle at the oil-to-water surface?
a. 18.1°
c. 27.3°
b. 24.2°
d. 37.0°
____ 31. An oil film floats on a water surface. The indices of refraction for water and oil, respectively, are 1.333 and
1.466. If a ray of light is incident on the air-to-oil surface at an angle of 37.0° with the normal, what is the
angle of the refracted ray in the water?
a. 18.1°
c. 26.8°
b. 24.2°
d. 37.0°
____ 32. Light in air enters a diamond (n = 2.42) at an angle of incidence of 48.0°. What is the angle of refraction
inside the diamond?
a. 17.9°
c. 24.7°
b. 19.8°
d. 45.6°
____ 33. An underwater scuba diver sees the sun at an apparent angle of 30.0° from the vertical. How far is the sun
above the horizon? (nwater = 1.333)
a. 22.0°
c. 48.2°
b. 41.8°
d. 68.0°
____ 34. A light beam is incident upon a still water surface. What is the maximum possible value for the angle of
refraction? (nwater = 1.333).
a. 76.2°
c. 54.4°
b. 67.5°
d. 48.6°
____ 35. A beam of light is incident upon a flat piece of glass (n = 1.50) at an angle of incidence of 45. Part of the
beam is transmitted and part is reflected. What is the angle between the reflected and transmitted rays?
a. 28
c. 107
b. 73
d. 152
____ 36. Of the values listed below, which is the greatest possible value for the index of refraction?
a. 1.5
c. 2.0
3
d. 2.4
b.
____ 37. A certain kind of glass has nblue = 1.650 for blue light and nred = 1.610 for red light. If a beam of white light
(containing all colors) is incident at an angle of 30.0°, what is the angle between the red and blue light inside
the glass?
a. 0.22°
c. 1.90°
b. 0.45°
d. 1.81°
4
____ 38. Diamond has an index of refraction of 2.419. What is the critical angle for internal reflection inside a diamond
that is in air?
a. 24.4°
c. 155°
b. 48.8°
d. 131°
____ 39. A ray of light travels across a liquid-to-glass interface. If the indices of refraction for the liquid and glass are,
respectively, 1.75 and 1.52, what is the critical angle at this interface?
a. 30.0°
c. 60.3°
b. 52.2°
d. Critical angle does not exist.
____ 40. A fiber optic cable (n = 1.50) is submerged in water (n = 1.33). What is the critical angle for light to stay
inside the cable?
a. 83.1°
c. 41.8°
b. 62.5°
d. 27.6°
____ 41. An optical fiber is made of clear plastic with index of refraction n = 1.50. For what angles with the surface
will light remain within the plastic “guide”?
c.  < 51.7°
a.  < 66.6°
b.  < 57.1°
d.  < 48.2°
____ 42. Before light can undergo total internal reflection when incident on material 2 from material 1, what must be
true of the indices of refraction?
c. n1 > n2
a. n1 = n2
b. n1 < n2
d. Either n1 or n2 must be equal to 1.
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ID: A
Reflection and Refraction
Answer Section
MULTIPLE CHOICE
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D
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ID: A
41. D
42. C
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