Question 1

The largest x-ray wavelength that can be diffracted by crystal planes with a separation of 0.316 nm is:

Accepted Answer

A) 0.158 nm 
B) 0.316 nm 
C) 0.474 nm 
D) 0.632 nm 
E) 1.26 nm 
A) 0.158 nm 
B) 0.316 nm 
C) 0.474 nm 
D) 0.632 nm 
E) 1.26 nm

Question 2

Monochromatic light is normally incident on a diffraction grating.The mth order line is at an angle of diffraction $\theta$ and has width w.A wide single slit is now placed in front of the grating and its width is then slowly reduced.As a result:

Accepted Answer

A) "both $\theta$ and w increase" 
B) "both $\theta$ and w decrease" 
C) "$\theta$ remains the same and w increases" 
D) "$\theta$ remains the same and w decreases" 
E) "$\theta$ decreases and w increases" 
A) "both $\theta$ and w increase" 
B) "both $\theta$ and w decrease" 
C) "$\theta$ remains the same and w increases" 
D) "$\theta$ remains the same and w decreases" 
E) "$\theta$ decreases and w increases"

Question 3

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 spreading apart of diffraction lines associated with different wavelengths 
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 spreading apart of diffraction lines associated with different wavelengths

Question 4

In a single-slit diffraction pattern, the central maximum is about twice as wide as the other maxima.This is because:

Accepted Answer

A) half the light is diffracted up and half is diffracted down 
B) the central maximum has both electric and magnetic fields present 
C) the small angle approximation applies only near the central maximum 
D) the screen is flat instead of spherical 
E) none of the above 
A) half the light is diffracted up and half is diffracted down 
B) the central maximum has both electric and magnetic fields present 
C) the small angle approximation applies only near the central maximum 
D) the screen is flat instead of spherical 
E) none of the above

Question 5

The resolving power of a diffraction grating is defined by R = $\lambda$/$\Delta$$\lambda$.Here $\lambda$and $\lambda$+$\Delta$$\lambda$are:

Accepted Answer

A) any two wavelengths 
B) any two wavelengths that are nearly the same 
C) two wavelengths for which lines of the same order are separated by  $\pi$ radians 
D) two wavelengths for which lines of the same order are separated by 2 $\pi$ radians 
E) two wavelengths for which lines of the same order are separated by half the width of a maximum 
A) any two wavelengths 
B) any two wavelengths that are nearly the same 
C) two wavelengths for which lines of the same order are separated by  $\pi$ radians 
D) two wavelengths for which lines of the same order are separated by 2 $\pi$ radians 
E) two wavelengths for which lines of the same order are separated by half the width of a maximum

Question 6

Bragg's law for x-ray diffraction is 2d sin$\theta$= m$\lambda$, where$\theta$is the angle between the incident beam and:

Accepted Answer

A) a reflecting plane of atoms 
B) the normal to a reflecting plane of atoms 
C) the scattered beam 
D) the normal to the scattered beam 
E) the refracted beam 
A) a reflecting plane of atoms 
B) the normal to a reflecting plane of atoms 
C) the scattered beam 
D) the normal to the scattered beam 
E) the refracted beam

Question 7

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 8

Two slits in an opaque barrier each have a width of 0.020 mm and are separated by 0.050 mm.When coherent monochromatic light passes through the slits the number of interference maxima within the central diffraction maximum:

Accepted Answer

A) is 1 
B) is 2 
C) is 4 
D) is 5 
E) cannot be determined unless the wavelength is given 
A) is 1 
B) is 2 
C) is 4 
D) is 5 
E) cannot be determined unless the wavelength is given

Question 9

The intensity at a secondary maximum of a single-slit diffraction pattern is less than the intensity at the central maximum chiefly because:

Accepted Answer

A) some Huygens wavelets sum to zero at the secondary maximum but not at the central maximum 
B) the secondary maximum is further from the slits than the central maximum and intensity decreases as the square of the distance 
C) the Huygens construction is not valid for a secondary maximum 
D) the amplitude of every Huygens wavelet is smaller when it travels to a secondary maximum than when it travels to the central maximum 
E) none of the above 
A) some Huygens wavelets sum to zero at the secondary maximum but not at the central maximum 
B) the secondary maximum is further from the slits than the central maximum and intensity decreases as the square of the distance 
C) the Huygens construction is not valid for a secondary maximum 
D) the amplitude of every Huygens wavelet is smaller when it travels to a secondary maximum than when it travels to the central maximum 
E) none of the above

Question 10

When light of a certain wavelength is incident normally on a certain diffraction grating the line of order 1 is at a diffraction angle of 25 $\degree$.The diffraction angle for the second order line is:

Accepted Answer

A) 25 $\degree$ 
B) 42 $\degree$ 
C) 50 $\degree$ 
D) 58 $\degree$ 
E) 75 $\degree$ 
A) 25 $\degree$ 
B) 42 $\degree$ 
C) 50 $\degree$ 
D) 58 $\degree$ 
E) 75 $\degree$

Question 11

600-nm light is incident on a diffraction grating with a ruling separation of 1.7 *10-6 m.The second order line occurs at a diffraction angle of:

Accepted Answer

A) 0° 
B) 10 $\degree$ 
C) 21 $\degree$ 
D) 42 $\degree$ 
E) 45 $\degree$ 
A) 0° 
B) 10 $\degree$ 
C) 21 $\degree$ 
D) 42 $\degree$ 
E) 45 $\degree$

Question 12

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

Question 13

In the equation d sin$\theta$ = m$\lambda$ for the lines of a diffraction grating, d is:

Accepted Answer

A) the number of slits 
B) the slit width 
C) the slit separation 
D) the order of the line 
E) the index of refraction 
A) the number of slits 
B) the slit width 
C) the slit separation 
D) the order of the line 
E) the index of refraction

Question 14

A point source of monochromatic light is placed in front of a soccer ball and a screen is placed behind the ball.The light intensity pattern on the screen is best described as:

Accepted Answer

A) a dark disk on a bright background 
B) a dark disk with bright rings outside 
C) a dark disk with a bright spot at its center 
D) a dark disk with a bright spot at its center and bright rings outside 
E) a bright disk with bright rings outside 
A) a dark disk on a bright background 
B) a dark disk with bright rings outside 
C) a dark disk with a bright spot at its center 
D) a dark disk with a bright spot at its center and bright rings outside 
E) a bright disk with bright rings outside

Question 15

Light of wavelength 550 nm is incident on a diffraction grating that is 1 cm wide and has 1000 slits.What is the half-width of the m = 1 line?

Accepted Answer

A) 5.5 x 10-5 rad 
B) 5.5 x 10-4 rad 
C) 5.5 x 10-3 rad 
D) 5.5 x 10-2 rad 
E) 5.5 x 10-1 rad 
A) 5.5 x 10-5 rad 
B) 5.5 x 10-4 rad 
C) 5.5 x 10-3 rad 
D) 5.5 x 10-2 rad 
E) 5.5 x 10-1 rad

Question 16

A light spectrum is formed on a screen using a diffraction grating.The entire apparatus (source, grating and screen)is now immersed in a liquid of index 1.33.As a result, the pattern on the screen:

Accepted Answer

A) remains the same 
B) spreads out 
C) crowds together 
D) becomes reversed, with the previously blue end becoming red 
E) disappears because the index isn't an integer 
A) remains the same 
B) spreads out 
C) crowds together 
D) becomes reversed, with the previously blue end becoming red 
E) disappears because the index isn't an integer

Question 17

A diffraction grating of width W produces a deviation $\theta$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 18

In order to obtain a single-slit diffraction pattern with a central maximum and several secondary maxima, the slit width could be:

Accepted Answer

A) "$\lambda$" 
B) "$\lambda$/10" 
C) "10$\lambda$" 
D) "104$\lambda$" 
E) "$\lambda$/104" 
A) "$\lambda$" 
B) "$\lambda$/10" 
C) "10$\lambda$" 
D) "104$\lambda$" 
E) "$\lambda$/104"

Question 19

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 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) 0.066 rad 
D) 0.033 rad 
E) 0.0033 rad 
A) 0.70 rad 
B) 0.33 rad 
C) 0.066 rad 
D) 0.033 rad 
E) 0.0033 rad

Exam 36: Diffraction

The largest x-ray wavelength that can be diffracted by crystal planes with a separation of 0.316 nm is:

Monochromatic light is normally incident on a diffraction grating.The mth order line is at an angle of diffraction θ\thetaθ and has width w.A wide single slit is now placed in front of the grating and its width is then slowly reduced.As a result:

The dispersion of a diffraction grating indicates:

In a single-slit diffraction pattern, the central maximum is about twice as wide as the other maxima.This is because:

The resolving power of a diffraction grating is defined by R = λ\lambdaλ / Δ\DeltaΔλ\lambdaλ .Here λ\lambdaλ and λ\lambdaλ + Δ\DeltaΔλ\lambdaλ are:

Bragg's law for x-ray diffraction is 2d sin θ\thetaθ = m λ\lambdaλ , where θ\thetaθ is the angle between the incident beam and:

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:

Two slits in an opaque barrier each have a width of 0.020 mm and are separated by 0.050 mm.When coherent monochromatic light passes through the slits the number of interference maxima within the central diffraction maximum:

The intensity at a secondary maximum of a single-slit diffraction pattern is less than the intensity at the central maximum chiefly because:

When light of a certain wavelength is incident normally on a certain diffraction grating the line of order 1 is at a diffraction angle of 25 °\degree° .The diffraction angle for the second order line is:

600-nm light is incident on a diffraction grating with a ruling separation of 1.7 *10-6 m.The second order line occurs at a diffraction angle of:

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

In the equation d sin θ\thetaθ = m λ\lambdaλ for the lines of a diffraction grating, d is:

A point source of monochromatic light is placed in front of a soccer ball and a screen is placed behind the ball.The light intensity pattern on the screen is best described as:

Light of wavelength 550 nm is incident on a diffraction grating that is 1 cm wide and has 1000 slits.What is the half-width of the m = 1 line?

A light spectrum is formed on a screen using a diffraction grating.The entire apparatus (source, grating and screen)is now immersed in a liquid of index 1.33.As a result, the pattern on the screen:

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

In order to obtain a single-slit diffraction pattern with a central maximum and several secondary maxima, the slit width could be:

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

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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Monochromatic light is normally incident on a diffraction grating.The m^th order line is at an angle of diffraction $\theta$ and has width w.A wide single slit is now placed in front of the grating and its width is then slowly reduced.As a result:

The resolving power of a diffraction grating is defined by R = $\lambda$ / $\Delta$ $\lambda$ .Here $\lambda$ and $\lambda$ + $\Delta$ $\lambda$ are:

Bragg's law for x-ray diffraction is 2d sin $\theta$ = m $\lambda$ , where $\theta$ is the angle between the incident beam and:

When light of a certain wavelength is incident normally on a certain diffraction grating the line of order 1 is at a diffraction angle of 25 $\degree$ .The diffraction angle for the second order line is:

600-nm light is incident on a diffraction grating with a ruling separation of 1.7 *10^-6 m.The second order line occurs at a diffraction angle of:

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

In the equation d sin $\theta$ = m $\lambda$ for the lines of a diffraction grating, d is:

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

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: