1. Of the following human eyes are most sensitive to:
 A. red light
 B. violet light
 C. blue light
 D. green light
 E. none of these (they are equally sensitive to all colors)

2. Maxwell's equations predict that the speed of light in free space is:
 A. an increasing function of frequency
 B. a decreasing function of frequency
 C. independent of frequency
 D. a function of the distance from the source
 E. a function of the size of the source

3. The speed of light in vacuum is about:
 A. 1100 ft/s
 B. 93 × 106 mi/s
 C. 6 × 1023 m/s
 D. 3 × 1010 cm/s
 E. 186,000 mph

4. Which of the following types of electromagnetic radiation travels at the greatest speed in vacuum?
 B. Visible light
 C. X rays
 D. Gamma rays
 E. All of these travel at the same speed

5. The theoretical upper limit for the frequency of electromagnetic waves is:
 A. just slightly greater than that of red light
 B. just slightly less than that of blue light
 C. the greatest x-ray frequency
 D. none of the above (there is no upper limit)
 E. none of the above but there is an upper limit

6. An electromagnetic wave is generated by:
 A. any moving charge
 B. any accelerating charge
 C. only a charge with changing acceleration
 D. only a charge moving in a circle
 E. only a charge moving in a straight line

7.

The electric field for a plane electromagnetic wave traveling in the +y direction is shown. Consider a point where ® is in the +z direction. The 4 field is:

 A. in the +x direction and in phase with the ® field
 B. in the –x direction and in phase with the ® field
 C. in the +x direction and 1/4 wave out of phase with the ® field
 D. in the +z direction and in phase with the ® field
 E. in the +z direction and 1/4 wave out of phase with the ® field

8. In a plane electromagnetic wave in vacuum, the ratio E/B of the amplitudes in SI units of the two fields is:
 A. the speed of light
 B. an increasing function of frequency
 C. a decreasing function of frequency
 D.
 E.

9. If the electric field in a plane electromagnetic wave is along the y axis and its component is given by Emsin(kxwt), in SI units, then the magnetic field is along the z axis and its component is given by:
 A. (Em/c)cos(kx – wt)
 B. –(Em/c)cos(kx – wt)
 C. –(Em/c)sin(kx – wt)
 D. Emcos(kx – wt)
 E. (Em/c)sin(kx – wt)

10. If the electric field in a plane electromagnetic wave is along the y axis and its component is given by Emsin(kx + wt), in SI units, then the magnetic field is along the z axis and its component is given by:
 A. (Em/c)cos(kx + wt)
 B. –(Em/c)cos(kx + wt)
 C. –(Em/c)sin(kx + wt)
 D. Emcos(kx + wt)
 E. (Em/c)sin(kx + wt)

11. An electromagnetic wave is traveling in the positive x direction with its electric field along the z axis and its magnetic field along the y axis. The fields are related by:
 A. ¶E/¶x = m050¶B/¶x
 B. ¶E/¶x = m050¶B/¶t
 C. ¶B/¶x = m050¶E/¶x
 D. ¶B/¶x = m050¶E/¶t
 E. ¶B/¶x = –m050¶E/¶t

12. For an electromagnetic wave the direction of the vector ® × 4 gives:
 A. the direction of the electric field
 B. the direction of the magnetic field
 C. the direction of wave propagation
 D. the direction of the electromagnetic force on a proton
 E. the direction of the emf induced by the wave

13. At a certain point and a certain time the electric field of an electromagnetic wave is in the negative z direction and the magnetic field is in the positive y direction. Which of the following statements is true?
 A. Energy is being transported in the positive x direction but half a cycle later, when the electric field is in the opposite direction, it will be transported in the negative x direction
 B. Energy is being transported in the positive x direction and half a cycle later, when the electric field is in the opposite direction, it will still be transported in the positive x direction
 C. Energy is being transported in the negative x direction but half a cycle later, when the electric field is in the opposite direction, it will be transported in the positive x direction
 D. Energy is being transported in the negative x direction and half a cycle later, when the electric field is in the opposite direction, it will still be transported in the negative x direction.
 E. None of the above are true.

14. Evidence that electromagnetic waves carry momentum is:
 A. the tail of a comet points away from the sun
 B. electron flow through a wire generates heat
 C. a charged particle in a magnetic field moves in a circular orbit
 D. heat can be generated by rubbing two sticks together
 E. the Doppler effect

15. The relation qincident = qreflected, which applies as a ray of light strikes an interface between two media, is known as:
 B. Snell's law
 C. Ampere's law
 D. Cole's law
 E. none of these

16. The relation n1sinq1 = n2 sin q2 which applies as a ray of light strikes an interface between two media, is known as:
 A. Gauss' law
 B. Snell's law
 D. Cole's law
 E. law of sines

17. When an electromagnetic wave meets a reflecting surface, the direction taken by the reflected wave is determined by:
 A. the material of the reflecting surface
 B. the angle of incidence
 C. the index of the medium
 D. the intensity of the wave
 E. the wavelength

18. The index of refraction of a substance is:
 A. the speed of light in the substance
 B. the angle of refraction
 C. the angle of incidence
 D. the speed of light in vacuum divided by the speed of light in the substance

19. The units of index of refraction are:
 A. m/s
 B. s/m
 D. m/s2
 E. none of these

20.

The diagram shows the passage of a ray of light from air into a substance X. The index of refraction of X is:

 A. 0.74
 B. 1.15
 C. 1.29
 D. 1.35
 E. 1.47

21.

If nwater = 1.33, what is the angle of refraction for the ray shown?

 A. 19°
 B. 22°
 C. 36°
 D. 42°
 E. 48°

22.

Which diagram below illustrates the path of a light ray as it travels from a given point X in air to another given point Y in glass?

 A. I
 B. II
 C. III
 D. IV
 E. V

23.

The index of refraction for diamond is 2.5. Which of the following is correct for the situation shown?

 A. (sin a)/(sin b) = 2.5
 B. (sin b)/(sin d) = 2.5
 C. (cos a)/(cos c) = 2.5
 D. (sin a)/(sin c) = 1/(2.5)
 E. a/c = 2.5

24.

When light travels from medium X to medium Y as shown:

 A. both the speed and the frequency decrease
 B. both the speed and the frequency increase
 C. both the speed and the wavelength decrease
 D. both the speed and the wavelength increase
 E. both the wavelength and the frequency are unchanged

25.

A ray of light passes through three media as shown. The speed of light in these media obey:

 A. v1 > v2 > v3
 B. v3 > v2 > v1
 C. v3 > v1 > v2
 D. v2 > v1 > v3
 E. v1 > v3 > v2

26.

The rectangular metal tank shown is filled with an unknown liquid. The observer, whose eye is level with the top of the tank, can just see corner E. The index of refraction of this liquid is:

 A. 1.75
 B. 1.67
 C. 1.5
 D. 1.33
 E. 1.25

27. The separation of white light into colors by a prism is associated with:
 A. total internal reflection
 B. partial reflection from each surface
 C. variation of index of refraction with wavelength
 D. a decrease in the speed of light in the glass
 E. selective absorption of various colors

28. A virtual image is one:
 A. toward which light rays converge but do not pass through
 B. from which light rays diverge but do not pass through
 C. from which light rays diverge as they pass through
 D. toward which light rays converge and pass through
 E. with a ray normal to a mirror passing through it

29. A parallel beam of monochromatic light in air is incident on a plane glass surface. In the glass, the beam:
 A. remains parallel
 B. undergoes dispersion
 C. becomes diverging
 D. follows a parabolic path
 E. becomes converging

30. A concave refracting surface is one with a center of curvature:
 A. to the left of the surface
 B. to the right of the surface
 C. on the side of the incident light
 D. on the side of the refracted light
 E. on the side with the higher index of refraction

31. A convex refracting surface has a radius of 12 cm. Light is incident in air (n = 1) and refracted into a medium with an index of refraction of 2. To obtain light with rays parallel to the central axis after refraction a point source should be placed on the axis:
 A. 3 cm from the surface
 B. 6 cm from the surface
 C. 12 cm from the surface
 D. 18 cm from the surface
 E. 24 cm from the surface

32. An erect object is placed on the central axis of a thin lens, further from the lens than the magnitude of its focal length. The magnification is +0.4. This means:
 A. the image is real and erect and the lens is a converging lens
 B. the image is real and inverted and the lens is a converging lens
 C. the image is virtual and erect, and the lens is a diverging lens
 D. the image is virtual and erect, and the lens is a converging lens
 E. the image is virtual and inverted and the lens is a diverging lens

33. Where must an object be placed in front of a converging lens in order to obtain a virtual image?
 A. At the focal point
 B. At twice the focal length
 C. Greater than the focal length
 D. Between the focal point and the lens
 E. Between the focal length and twice the focal length

34. An erect object placed outside the focal point of a converging lens will produce an image that is:
 A. erect and virtual
 B. inverted and virtual
 C. erect and real
 D. inverted and real
 E. impossible to locate

35.

A hollow lens is made of thin glass as shown. It can be filled with air, water (n = 1.3) or CS2 (n = 1.6). The lens will diverge a beam of parallel light if it is filled with:

 A. air and immersed in air
 B. air and immersed in water
 C. water and immersed in CS2
 D. CS2 and immersed in water
 E. CS2 and immersed in CS2

36. The object-lens distance for a certain converging lens is 400 mm. The image is three times the size of the object. To make the image five times the size of the object-lens distance must be changed to:
 A. 360 mm
 B. 540 mm
 C. 600 mm
 D. 720 mm
 E. 960 mm

37. An erect object is 2f in front of a convex lens of focal length f. The image is:
 A. real, inverted, magnified
 B. real, erect, same size
 C. real, inverted, same size
 D. virtual, inverted, reduced
 E. real, inverted, reduced

38. When a single-lens camera is focused on a distant object, the lens-to-film distance is found to be 40.0 mm. To focus on an object 0.54 m in front of the lens, the film-to-lens distance must be:
 A. not changed
 B. decreased by 2.7 mm
 C. decreased by 3.2 mm
 D. increased by 2.7 mm
 E. increased by 3.2 mm

39. In a cinema, a picture 2.5 cm wide on the film is projected to an image 3.0 m wide on a screen which is 18 m away. The focal length of the lens is about:
 A. 7.5 cm
 B. 10 cm
 C. 12.5 cm
 D. 15 cm
 E. 20 cm

40. A "wave front" is a surface of constant:
 A. phase
 B. frequency
 C. wavelength
 D. amplitude
 E. speed

41. Huygens' construction can be used only:
 A. for light
 B. for an electromagnetic wave
 C. if one of the media is vacuum (or air)
 D. for transverse waves
 E. for all of these and other situations

42. Consider (I) the law of reflection and (II) the law of refraction. Huygens' principle can be used to derive:
 A. only I
 B. only II
 C. both I and II
 D. neither I nor II
 E. the question is meaningless because Huygen's principle is for wave fronts whereas both I and II concern rays

43. Units of "optical path length" are:
 A. m–1
 B. m
 C. m/s
 D. Hz/m
 E. m/Hz

44. Interference of light is evidence that:
 A. the speed of light is very large
 B. light is a transverse wave
 C. light is electromagnetic in character
 D. light is a wave phenomenon
 E. light does not obey conservation of energy

45. In a Young's double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in the distance they travel by a multiple of:
 A. a fourth of a wavelength
 B. a half a wavelength
 C. a wavelength
 D. three-fourths of a wavelength
 E. none of the above

46. In a Young's double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in phase by a multiple of:
 A. p/4
 B. p/2
 C. p
 D. 3p/4
 E. none of the above

47. Waves from two slits are in phase at the slits and travel to a distant screen to produce the second side maximum of the interference pattern. The difference in the distance traveled by the waves is:
 A. half a wavelength
 B. a wavelength
 C. three halves of a wavelength
 D. two wavelengths
 E. five halves of a wavelength

48. A monochromatic light source illuminates a double slit and the resulting interference pattern is observed on a distant screen. Let d = center-to-center slit spacing, a = individual slit width, D = screen-to-slit distance, E = adjacent dark line spacing in the interference pattern. The wavelength of the light is then:
 A. dE /D
 B. Ld/a
 C. da/D
 D. E D/a
 E. Dd/E

49. In a Young's double-slit experiment, light of wavelength 500 nm illuminates two slits which are separated by 1 mm. The separation between adjacent bright fringes on a screen 5 m from the slits is:
 A. 0.10 cm
 B. 0.25 cm
 C. 0.50 cm
 D. 1.0 cm
 E. none of the above

50. In an experiment to measure the wavelength of light using a double slit, it is found that the fringes are too close together to easily count them. To spread out the fringe pattern, one could:
 A. halve the slit separation
 B. double the slit separation
 C. double the width of each slit
 D. halve the width of each slit
 E. none of these

51. A light wave with an electric field amplitude of 2E0 and a phase constant of zero is to be combined with one of the following waves. Which of these combinations produces the greatest intensity?
 A. wave A has an amplitude of E0 and a phase constant of zero
 B. wave B has an amplitude of E0 and a phase constant of p
 C. wave C has an amplitde of 2E0 and a phase constant of zero
 D. wave D has an amplitude of 2E0 and a phase constant of p
 E. wave E has an amplitude of 3E0 and a phase constant of p

52.

Binoculars and microscopes are frequently made with "coated optics" by adding a thin layer of transparent material to the lens surface as shown. One wants:

 A. constructive interference between 1 and 2
 B. the coating to be more transparent than the lens
 C. destructive interference between 3 and 4
 D. the speed of light in the coating to be less than that in the lens
 E. destructive interference between 1 and 2

53. Monochromatic light, at normal incidence, strikes a thin film in air. If l denotes the wavelength in the film, what is the thinnest film in which the reflected light will be a maximum?
 A. much less than l
 B. l/4
 C. l/2
 D. 3l/4
 E. l

54. A soap film, 4 × 10–5 cm thick, is illuminated by white light normal to its surface. The index of refraction of the film is 1.50. Which wavelengths will be intensified in the reflected beam?
 A. 400 nm and 600 nm
 B. 480 nm and 800 nm
 C. 360 nm and 533 nm
 D. 400 nm and 800 nm
 E. 510 nm and 720 nm

55.

Red light is viewed through a thin vertical soap film. At the second dark area shown, the thickness of the film, in terms of the wavelength within the film, is:

 A. l
 B. 3l/4
 C. l/2
 D. l/4
 E. much less than l

56.

Yellow light is viewed by reflection from a thin vertical soap film. Let l be the wavelength of the light within the film. Why is there a large dark space at the top of the film?

 A. no light is transmitted through this part of the film
 B. the film thickness there is l/4
 C. the light reflected from exactly one of the two surfaces undergoes a 180° phase change
 D. the film is too thick in this region for thin film formulas to apply
 E. the reflected light is in the infrared

57.

Three experiments involving a thin film (in air) are shown. If t denotes the film thickness and l denotes the wavelength of the light in the film, which experiments will produce constructive interference as seen by the observer?

 A. I only
 B. II only
 C. III only
 D. I and III only
 E. II and III only

58.

A lens with a refractive index of 1.5 is coated with a material of refractive index 1.2 in order to minimize reflection. If l denotes the wavelength of the incident light in air, what is the thinnest possible such coating?

 A. 0.5l
 B. 0.416l
 C. 0.3l
 D. 0.208l
 E. 0.25l

59. If two light waves are coherent:
 A. their amplitudes are the same
 B. their frequencies are the same
 C. their wavelengths are the same
 D. their phase difference is constant
 E. the difference in their frequencies is constant

60. Sound differs from light in that sound:
 A. is not subject to diffraction
 B. is a torsional wave rather than a longitudinal wave
 C. does not require energy for its origin
 D. is a longitudinal wave rather than a transverse wave
 E. is always monochromatic

61. Radio waves are readily diffracted around buildings whereas light waves are negligibly diffracted around buildings. This is because radio waves:
 A. are plane polarized
 B. have much longer wavelengths than light waves
 C. have much shorter wavelengths than light waves
 D. are nearly monochromatic (single frequency)
 E. are amplitude modulated (AM)

62. Diffraction plays an important role in which of the following phenomena?
 A. The sun appears as a disk rather than a point to the naked eye
 B. Light is bent as it passes through a glass prism
 C. A cheerleader yells through a megaphone
 D. A farsighted person uses eyeglasses of positive focal length
 E. A thin soap film exhibits colors when illuminated with white light

63. In the equation sinq = l/a for single-slit diffraction, q is:
 A. the angle to the first minimum
 B. the angle to the second maximum
 C. the phase angle between the extreme rays
 D. Np where N is an integer
 E. (N + 1/2)p where N is an integer

64.

Monochromatic plane waves of light are incident normally on a single slit. Which one of the five figures below correctly shows the diffraction pattern observed on a distant screen?

 A. I
 B. II
 C. III
 D. IV
 E. V

65.

The diagram shows a single slit with the direction to a point P on a distant screen shown. At P, the pattern has its second minimum (from its central maximum). If X and Y are the edges of the slit, what is the path length difference (PX) – (PY)?

 A. l/2
 B. l
 C. 3l/2
 D. 2l
 E. 5l/2

66. A diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength l. If the slit width is decreased and no other changes are made:
 A. the intensity at the center of the pattern decreases and the pattern expands away from the bright center
 B. the intensity at the center increases and the pattern contracts toward the bright center
 C. the intensity at the center of the pattern does not change and the pattern expands away from the bright center
 D. the intensity at the center of the pattern does not change and the pattern contracts toward the bright center
 E. neither the intensity at the center of the pattern nor the pattern itself change

67. In order to obtain a good single-slit diffraction pattern, the slit width could be:
 A. l
 B. l/10
 C. 10l
 D. 104l
 E. l/104

68. Consider a single-slit diffraction pattern caused by a slit of width a. There is a maximum at sinq equal to:
 A. slightly more than 3l/2a
 B. slightly less than 3l/2a
 C. exactly 3l/2a
 D. exactly l/2a
 E. very nearly l/2a

69. Consider a single-slit diffraction pattern caused by a slit of width a. There is a minimum at sinq equal to:
 A. exactly l/a
 B. slightly more than l/a
 C. slightly less than l/a
 D. exactly l/2a
 E. very nearly l/2a

70.

Two wavelengths, 800 nm and 600 nm, are used separately in single-slit diffraction experiments. The diagram shows the intensities on a far-away viewing screen as function of the angle made by the rays with the straight-ahead direction. If both wavelengths are then used simultaneously, at which angle is the light on the screen purely 600-nm light?

 A. I
 B. II
 C. III
 D. IV
 E. V

71. Two slits of width a and separation d are illuminated by a beam of light of wavelength l. The separation of the interference fringes on a screen a distance D away is:
 A. la/D
 B. ld/D
 C. lD/d
 D. dD/l
 E. lD/a

72. In the equation d sinq = ml for the lines of a multiple-slit system m is:
 A. the number of slits
 B. the slit width
 C. the slit separation
 D. the order of the line
 E. the index of refraction

73. An N-slit system has slit separation d and slit width a. Plane waves with intensity I and wavelength l are incident normally on it. The angular separation of the lines depends only on:
 A. a and N
 B. a and l
 C. N and l
 D. d and l
 E. I and N

74. Monochromatic light is normally incident on a diffraction grating that is 1 cm wide and has 10,000 slits. The first order line is deviated at a 30° angle. What is the wavelength, in nm, of the incident light?
 A. 300
 B. 400
 C. 500
 D. 600
 E. 1000

75. A diffraction grating of width W produces a deviation q in second order for light of wavelength l. The total number N of slits in the grating is given by:
 A. 2Wl/sinq
 B. (W/l)sinq
 C. lW/2sinq
 D. (W/2l)sinq
 E. 2l/sinq

76.

A beam of white light (from 400 nm for violet to 700 nm for red) is normally incident on a diffraction grating. It produces two orders on a distant screen. Which diagram below (R = red, V = violet) correctly shows the pattern on the screen?

 A. I.
 B. II.
 C. III.
 D. IV.
 E. V.

77.

Light of wavelength is normally incident on some plane optical device. The intensity pattern shown is observed on a distant screen (q is the angle measured to the normal of the device). The device could be:

 A. a single slit of width W
 B. a single slit of width 2W
 C. two narrow slits with separation W
 D. two narrow slits with separation 2W
 E. a diffraction grating with slit separation W

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