Question 1

Two very flat pieces of glass touch at one edge and are held apart by a small wire at the other edge. Illumination from above by coherent light of wavelength 5000 angstroms results in 20 dark fringes between the touching surfaces and where the wire is located. The approximate diameter of the wire is

Accepted Answer

A)   200,000 angstroms.
B)   100,000 angstroms.
C)   50,000 angstroms.
D)   25,000 angstroms.E) A) and C)
F) None of the above

Question 2

The critical angle for two objects 1 meter apart is  10−610 ^ { - 6 }10−6  radians. Estimate the wavelength of the light:

Accepted Answer

A)   550 nm
B)   630 nm
C)   820 nm
D)   710 nm E) A) and B)
F) B) and C)

Question 3

If two sources emit waves that are of the same frequencies and are in phase, the interference fringes produced will appear to the human eye to be

Accepted Answer

A)   stationary in space.
B)   stationary in time.
C)   Both of the first two responses are valid.
D)   Neither of the first two responses is valid.E) B) and C)
F) B) and D)

Question 4

Find the critical angle for two objects 1 meter apart when viewed using 500-nm light (assume a circular aperture) :

Accepted Answer

A)    6×10−76 	imes 10 ^ { - 7 }6×10−7  radians
B)    4×10−54 	imes 10 ^ { - 5 }4×10−5  radians
C)    8×10−68 	imes 10 ^ { - 6 }8×10−6  radians
D)    5×10−65 	imes 10 ^ { - 6 }5×10−6  radians E) A) and B)
F) All of the above

Question 5

The angular separation between principal maxima for a grating consisting of 10,000 slits is 30º. The approximate angular width of the principal maxima is

Accepted Answer

A)   .003º.
B)   .3º.
C)   30º.
D)   Hold it! The angle is much greater than 360º.E) A) and D)
F) C) and D)

Question 6

When light reflects from a thin film, the distance between adjacent bright regions of the fringes depends on the film thickness being equal to the wavelength of the light times

Accepted Answer

A)   1/4.
B)   1/2.
C)   1.
D)   2.E) A) and D)
F) A) and C)

Question 7

The width of a principal maximum for a grating decreases with an increase in each of the following except

Accepted Answer

A)   the number of slits.
B)   the separation of slits.
C)   the wavelength of light.
D)   Hold it! There are no exceptions.E) A) and C)
F) A) and B) C

Question 8

The intensity   I 	ext { I } I   of an electromagnetic wave (having electric field  EEE  )  is proportional to

Accepted Answer

A)    EEE 
B)    E\sqrt { E }Ec-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​ 
C)    E2E ^ { 2 }E2 
D)    E4E ^ { 4 }E4E) C) and D)
F) A) and B)

Question 9

A monochromatic source produces light at a wavelength of 510 nm in air. The wave then passes through water that has an index of refraction of 1.32. The wavelength of the wave in the water is

Accepted Answer

A)   673 nm.
B)    386386386  nm.
C)   510 nm.
D)   623 nm. E) B) and C)
F) C) and D)

Question 10

When light reflects from a thin film, the distance between adjacent bright regions of the fringes depends on the path difference being equal to the wavelength of the light times

Accepted Answer

A)   1/4.
B)   1/2.
C)   1.
D)   2.E) None of the above
F) A) and C)

Question 11

The explanation for the correct response to the previous question involves the two facts that red light has a wavelength that is

Accepted Answer

A)   longer than that of blue light, and it travels slower in glass than blue light.
B)   longer than that of blue light, and it travels faster in glass than blue light.
C)   shorter than that of blue light, and it travels faster in glass than blue light.
D)   shorter than that of blue light, and it travels slower in glass than blue light.E) None of the above
F) A) and B)

Question 12

Direct observation of a standing wave pattern associated with light is difficult. The most relevant reason is that

Accepted Answer

A)   the eye is insensitive to fluctuations in intensity that occur at those frequencies.
B)   the eye cannot resolve a pattern with that spacing.
C)   there is no convenient means of setting up the conditions for standing waves.
D)   Hold it! In principle, light is not capable of producing standing waves.E) C) and D)
F) None of the above

Question 13

The width of the central maximum diffraction pattern produced by a single slit will increase when

Accepted Answer

A)   the slit width decreases.
B)   the slit width increases.
C)   the wavelength decreases.
D)   None of the previous answers is correct.E) None of the above
F) C) and D)

Question 14

In a Young's double-slit experiment, when  (πd/λ) sin⁡θ( \pi d / \lambda )  \sin 	heta(πd/λ) sinθ  is a multiple of (  π(π,2π,3π) \pi ( \pi , 2 \pi , 3 \pi ) π(π,2π,3π)   ) , the intensity at the viewing screen

Accepted Answer

A)   is a maximum.
B)   is a minimum.
C)   is halfway between the maximum and minimum.
D)   cannot be determined (we need  d,λ, and θd , \lambda , 	ext { and } 	hetad,λ, and θ  )  E) B) and C)
F) B) and D)

Question 15

There is invariably a phase shift when light reflects from a surface such that the index of refraction in which the wave is propagating is

Accepted Answer

A)   > 1.
B)   > the index of the material beyond the reflecting surface.
C)   = the index of the material beyond the reflecting surface.
D)   < the index of the material beyond the reflecting surface.E) B) and C)
F) None of the above D

Question 16

When two pieces of glass are pressed together in air and illuminated with coherent light, the place where they are in contact will look

Accepted Answer

A)   dark.
B)   bright.
C)   Hold it! Its appearance will oscillate between dark and bright.
D)   Hold it! Though the appearance will be steady in time, more information is needed to answer this question unambiguously.E) None of the above
F) A) and D)

Question 17

In designing a grating, the way to achieve a larger angular separation of adjacent maxima for two approximately equal wavelengths is to

Accepted Answer

A)   make the slits closer together.
B)   increase the number of slits.
C)   look at larger-order maxima.
D)   Hold it! More than one response is valid.E) A) and C)
F) C) and D)

Question 18

When light reflects from a thin film, the distance between the fringes depends on all of the following except

Accepted Answer

A)   the change in film thickness.
B)   the light frequency.
C)   the index of refraction of the film.
D)   Hold it! There are no exceptions.E) All of the above
F) A) and B) D

Question 19

In designing a grating, the way to achieve a smaller angular spread from the maxima of each wavelength to the corresponding minima for two approximately equal wavelengths is to

Accepted Answer

A)   make the slits closer together.
B)   increase the number of slits.
C)   look at larger-order maxima.
D)   Hold it! More than one response is valid.E) A) and D)
F) A) and C)

Question 20

The second angular minima location for a single-slit diffraction having slit width of  1.5μm1.5 \mu \mathrm { m }1.5μm  and wavelength of 500 nm is

Accepted Answer

A)   13º.
B)   42º.
C)   25º.
D)   36º. E) B) and C)
F) C) and D)

Exam 35: Interference and Diffraction

Correct AnswerverifiedShow Answer

The critical angle for two objects 1 meter apart is 10−610 ^ { - 6 }10−6 radians. Estimate the wavelength of the light:

Correct AnswerverifiedShow Answer

If two sources emit waves that are of the same frequencies and are in phase, the interference fringes produced will appear to the human eye to be

Correct AnswerverifiedShow Answer

Find the critical angle for two objects 1 meter apart when viewed using 500-nm light (assume a circular aperture) :

Correct AnswerverifiedShow Answer

The angular separation between principal maxima for a grating consisting of 10,000 slits is 30º. The approximate angular width of the principal maxima is

Correct AnswerverifiedShow Answer

When light reflects from a thin film, the distance between adjacent bright regions of the fringes depends on the film thickness being equal to the wavelength of the light times

Correct AnswerverifiedShow Answer

The width of a principal maximum for a grating decreases with an increase in each of the following except

Correct AnswerverifiedC

The intensity I \text { I } I of an electromagnetic wave (having electric field EEE ) is proportional to

Correct AnswerverifiedShow Answer

A monochromatic source produces light at a wavelength of 510 nm in air. The wave then passes through water that has an index of refraction of 1.32. The wavelength of the wave in the water is

Correct AnswerverifiedShow Answer

When light reflects from a thin film, the distance between adjacent bright regions of the fringes depends on the path difference being equal to the wavelength of the light times

Correct AnswerverifiedShow Answer

The explanation for the correct response to the previous question involves the two facts that red light has a wavelength that is

Correct AnswerverifiedShow Answer

Direct observation of a standing wave pattern associated with light is difficult. The most relevant reason is that

Correct AnswerverifiedShow Answer

The width of the central maximum diffraction pattern produced by a single slit will increase when

Correct AnswerverifiedShow Answer

In a Young's double-slit experiment, when (πd/λ) sin⁡θ( \pi d / \lambda ) \sin \theta(πd/λ) sinθ is a multiple of ( π(π,2π,3π) \pi ( \pi , 2 \pi , 3 \pi ) π(π,2π,3π) ) , the intensity at the viewing screen

Correct AnswerverifiedShow Answer

There is invariably a phase shift when light reflects from a surface such that the index of refraction in which the wave is propagating is

Correct AnswerverifiedD

When two pieces of glass are pressed together in air and illuminated with coherent light, the place where they are in contact will look

Correct AnswerverifiedShow Answer

In designing a grating, the way to achieve a larger angular separation of adjacent maxima for two approximately equal wavelengths is to

Correct AnswerverifiedShow Answer

When light reflects from a thin film, the distance between the fringes depends on all of the following except

Correct AnswerverifiedD

In designing a grating, the way to achieve a smaller angular spread from the maxima of each wavelength to the corresponding minima for two approximately equal wavelengths is to

Correct AnswerverifiedShow Answer

The second angular minima location for a single-slit diffraction having slit width of 1.5μm1.5 \mu \mathrm { m }1.5μm and wavelength of 500 nm is

Correct AnswerverifiedShow Answer

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The critical angle for two objects 1 meter apart is $10 ^ { - 6 }$ radians. Estimate the wavelength of the light:

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C

The intensity $\text { I }$ of an electromagnetic wave (having electric field $E$ ) is proportional to

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In a Young's double-slit experiment, when $( \pi d / \lambda ) \sin \theta$ is a multiple of ( $\pi ( \pi , 2 \pi , 3 \pi )$ ) , the intensity at the viewing screen

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D

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D

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The second angular minima location for a single-slit diffraction having slit width of $1.5 \mu \mathrm { m }$ and wavelength of 500 nm is

Correct Answer
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