Question 1

Bragg's law for x-ray diffraction is 2d sin$\theta$= m$\lambda$, the quantity d is:

Accepted Answer

A)  the height of a unit cell 
B)  the smallest interatomic distance 
C)  the distance from detector to sample 
D)  the distance between planes of atoms 
E)  the usual calculus symbol for a differential 
A)  the height of a unit cell 
B)  the smallest interatomic distance 
C)  the distance from detector to sample 
D)  the distance between planes of atoms 
E)  the usual calculus symbol for a differential D

Question 2

The shimmering or wavy lines that can often be seen near the ground on a hot day are due to:

Accepted Answer

A)  Brownian movement 
B)  reflection 
C)  refraction 
D)  diffraction 
E)  dispersion 
A)  Brownian movement 
B)  reflection 
C)  refraction 
D)  diffraction 
E)  dispersion C

Question 3

The resolving power R of a grating can have units:

Accepted Answer

A)  cm 
B)  degree/nm 
C)  watt 
D)  nm/cm 
E)  watt/nm 
A)  cm 
B)  degree/nm 
C)  watt 
D)  nm/cm 
E)  watt/nm D

Question 4

To obtain greater dispersion by a diffraction grating:

Accepted Answer

A)  the slit width should be increased 
B)  the slit width should be decreased 
C)  the slit separation should be increased 
D)  the slit separation should be decreased 
E)  more slits with the same width and separation should be added to the system 
A)  the slit width should be increased 
B)  the slit width should be decreased 
C)  the slit separation should be increased 
D)  the slit separation should be decreased 
E)  more slits with the same width and separation should be added to the system

Question 5

Diffraction plays an important role in which of the following phenomena?

Accepted Answer

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 
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

Question 6

A beam of x rays of wavelength 0.10nm is found to diffract in second order from the face of a LiF crystal at a Bragg angle of 30$\degree$. The distance between adjacent crystal planes, in nm, is about:

Accepted Answer

A)  0.15 
B)  0.20 
C)  0.25 
D)  0.30 
E)  0.40 
A)  0.15 
B)  0.20 
C)  0.25 
D)  0.30 
E)  0.40

Question 7

The dispersion of a diffraction grating indicates:

Accepted Answer

A)  the resolution of the grating 
B)  the separation of lines of the same order 
C)  the number of rulings in the grating 
D)  the width of the lines 
E)  the separation of lines of different order for the same wavelength 
A)  the resolution of the grating 
B)  the separation of lines of the same order 
C)  the number of rulings in the grating 
D)  the width of the lines 
E)  the separation of lines of different order for the same wavelength

Question 8

A diffraction-limited laser of length   and aperture diameter d generates light of wavelength $\lambda$. If the beam is directed at the surface of the Moon a distance D away, the radius of the illuminated area on the moon is approximately:

Accepted Answer

A)    
B)  dD/$\lambda$ 
C)    
D)  D$\lambda$/d 
E)    
A)    
B)  dD/$\lambda$ 
C)    
D)  D$\lambda$/d 
E)

Question 9

An N-slit system has slit separation d and slit width a. Plane waves with intensity I and wavelength $\lambda$ are incident normally on it. The angular separation of the lines depends only on:

Accepted Answer

A)  a and N 
B)  a and $\lambda$ 
C)  N and $\lambda$ 
D)  d and $\lambda$ 
E)  I and N 
A)  a and N 
B)  a and $\lambda$ 
C)  N and $\lambda$ 
D)  d and $\lambda$ 
E)  I and N

Question 10

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

Accepted Answer

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 
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

Question 11

The spacing between adjacent slits on a diffraction grating is 3$\lambda$. The deviation $\theta$of the first order diffracted beam is given by:

Accepted Answer

A)  sin($\theta$/2) = 1/3 
B)  sin($\theta$/3) = 2/3 
C)  sin($\theta$) = 1/3 
D)  tan($\theta$/2) = 1/3 
E)  tan($\theta$) = 2/3 
A)  sin($\theta$/2) = 1/3 
B)  sin($\theta$/3) = 2/3 
C)  sin($\theta$) = 1/3 
D)  tan($\theta$/2) = 1/3 
E)  tan($\theta$) = 2/3

Question 12

Figure (i) shows a double-slit pattern obtained using monochromatic light. Consider the following five possible changes in conditions:   Which of the above would change Figure (i) into Figure (ii)?

Accepted Answer

A)  3 only 
B)  5 only 
C)  1 and 3 only 
D)  1 and 5 only 
E)  2 and 4 only 
A)  3 only 
B)  5 only 
C)  1 and 3 only 
D)  1 and 5 only 
E)  2 and 4 only

Question 13

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern the phase difference between the Huygens wavelet from the top of the slit and the wavelet from the midpoint of the slit is:

Accepted Answer

A)   $\pi$/8 rad 
B)   $\pi$/4 rad 
C)   $\pi$/2 rad 
D)   $\pi$ rad 
E)  3 $\pi$/2 rad 
A)   $\pi$/8 rad 
B)   $\pi$/4 rad 
C)   $\pi$/2 rad 
D)   $\pi$ rad 
E)  3 $\pi$/2 rad

Question 14

No fringes are seen in a single-slit diffraction pattern if:

Accepted Answer

A)  the screen is far away 
B)  the wavelength is less than the slit width 
C)  the wavelength is greater than the slit width 
D)  the wavelength is less than the distance to the screen 
E)  the distance to the screen is greater than the slit width 
A)  the screen is far away 
B)  the wavelength is less than the slit width 
C)  the wavelength is greater than the slit width 
D)  the wavelength is less than the distance to the screen 
E)  the distance to the screen is greater than the slit width

Question 15

A diffraction grating of width W produces a deviation $\lambda$in second order for light of wavelength $\lambda$. The total number N of slits in the grating is given by:

Accepted Answer

A)  2W$\lambda$/sin$\theta$ 
B)  (W/$\lambda$)sin$\theta$ 
C)  $\lambda$W/2sin$\theta$ 
D)  (W/2$\lambda$)sin$\theta$ 
E)  2$\lambda$/sin$\theta$ 
A)  2W$\lambda$/sin$\theta$ 
B)  (W/$\lambda$)sin$\theta$ 
C)  $\lambda$W/2sin$\theta$ 
D)  (W/2$\lambda$)sin$\theta$ 
E)  2$\lambda$/sin$\theta$

Question 16

In the equation sin$\theta$ = $\lambda$/a for single-slit diffraction, $\theta$is:

Accepted Answer

A)  the angle to the first minimum 
B)  the angle to the second maximum 
C)  the phase angle between the extreme rays 
D)  N $\pi$where N is an integer 
E)  (N + 1/2) $\pi$ where N is an integer 
A)  the angle to the first minimum 
B)  the angle to the second maximum 
C)  the phase angle between the extreme rays 
D)  N $\pi$where N is an integer 
E)  (N + 1/2) $\pi$ where N is an integer

Question 17

A student wishes to produce a single-slit diffraction pattern in a ripple tank experiment. He considers the following parameters:   Which two of the above should be decreased to produce more bending?

Accepted Answer

A)  I, III 
B)  I, IV 
C)  II, III 
D)  II, IV 
E)  III, IV 
A)  I, III 
B)  I, IV 
C)  II, III 
D)  II, IV 
E)  III, IV

Question 18

When a highly coherent beam of light is directed against a very fine wire, the shadow formed behind it is not just that of a single wire but rather looks like the shadow of several parallel wires. The explanation of this involves:

Accepted Answer

A)  refraction 
B)  diffraction 
C)  reflection 
D)  Doppler effect 
E)  an optical illusion 
A)  refraction 
B)  diffraction 
C)  reflection 
D)  Doppler effect 
E)  an optical illusion

Question 19

Consider a single-slit diffraction pattern caused by a slit of width a. There is a minimum at sin$\theta$equal to:

Accepted Answer

A)  exactly $\lambda$/a 
B)  slightly more than $\lambda$/a 
C)  slightly less than $\lambda$/a 
D)  exactly $\lambda$/2a 
E)  very nearly$\lambda$/2a 
A)  exactly $\lambda$/a 
B)  slightly more than $\lambda$/a 
C)  slightly less than $\lambda$/a 
D)  exactly $\lambda$/2a 
E)  very nearly$\lambda$/2a

Question 20

A beam of x-rays of wavelength 0.20 nm is diffracted by a set of planes in a crystal whose separation is 3.1 *10-8 cm. The smallest angle between the beam and the crystal planes for which a reflection occurs is:

Accepted Answer

A)  0.70 rad 
B)  0.33 rad 
C)  0.033 rad 
D)  0.066 rad 
E)  no such angle exists 
A)  0.70 rad 
B)  0.33 rad 
C)  0.033 rad 
D)  0.066 rad 
E)  no such angle exists

Exam 36: Diffraction

Bragg's law for x-ray diffraction is 2d sin θ\thetaθ = m λ\lambdaλ , the quantity d is:

The shimmering or wavy lines that can often be seen near the ground on a hot day are due to:

The resolving power R of a grating can have units:

To obtain greater dispersion by a diffraction grating:

Diffraction plays an important role in which of the following phenomena?

A beam of x rays of wavelength 0.10nm is found to diffract in second order from the face of a LiF crystal at a Bragg angle of 30 °\degree° . The distance between adjacent crystal planes, in nm, is about:

The dispersion of a diffraction grating indicates:

A diffraction-limited laser of length and aperture diameter d generates light of wavelength λ\lambdaλ . If the beam is directed at the surface of the Moon a distance D away, the radius of the illuminated area on the moon is approximately:

An N-slit system has slit separation d and slit width a. Plane waves with intensity I and wavelength λ\lambdaλ are incident normally on it. The angular separation of the lines depends only on:

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

The spacing between adjacent slits on a diffraction grating is 3 λ\lambdaλ . The deviation θ\thetaθ of the first order diffracted beam is given by:

Figure (i) shows a double-slit pattern obtained using monochromatic light. Consider the following five possible changes in conditions: Which of the above would change Figure (i) into Figure (ii)?

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern the phase difference between the Huygens wavelet from the top of the slit and the wavelet from the midpoint of the slit is:

No fringes are seen in a single-slit diffraction pattern if:

A diffraction grating of width W produces a deviation λ\lambdaλ in second order for light of wavelength λ\lambdaλ . The total number N of slits in the grating is given by:

In the equation sin θ\thetaθ = λ\lambdaλ /a for single-slit diffraction, θ\thetaθ is:

A student wishes to produce a single-slit diffraction pattern in a ripple tank experiment. He considers the following parameters: Which two of the above should be decreased to produce more bending?

When a highly coherent beam of light is directed against a very fine wire, the shadow formed behind it is not just that of a single wire but rather looks like the shadow of several parallel wires. The explanation of this involves:

Consider a single-slit diffraction pattern caused by a slit of width a. There is a minimum at sin θ\thetaθ equal to:

A beam of x-rays of wavelength 0.20 nm is diffracted by a set of planes in a crystal whose separation is 3.1 *10-8 cm. The smallest angle between the beam and the crystal planes for which a reflection occurs is:

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Bragg's law for x-ray diffraction is 2d sin $\theta$ = m $\lambda$ , the quantity d is:

A beam of x rays of wavelength 0.10nm is found to diffract in second order from the face of a LiF crystal at a Bragg angle of 30 $\degree$ . The distance between adjacent crystal planes, in nm, is about:

An N-slit system has slit separation d and slit width a. Plane waves with intensity I and wavelength $\lambda$ are incident normally on it. The angular separation of the lines depends only on:

The spacing between adjacent slits on a diffraction grating is 3 $\lambda$ . The deviation $\theta$ of the first order diffracted beam is given by:

A diffraction grating of width W produces a deviation $\lambda$ in second order for light of wavelength $\lambda$ . The total number N of slits in the grating is given by:

In the equation sin $\theta$ = $\lambda$ /a for single-slit diffraction, $\theta$ is:

Consider a single-slit diffraction pattern caused by a slit of width a. There is a minimum at sin $\theta$ equal to:

A beam of x-rays of wavelength 0.20 nm is diffracted by a set of planes in a crystal whose separation is 3.1 *10^-⁸ cm. The smallest angle between the beam and the crystal planes for which a reflection occurs is: