Question 1

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 2

What is the minimum number of slits required in a deffraction grating to just resolve light with wavelengths of 471.0 nm and 471.6 nm?

Accepted Answer

A)  99 
B)  197 
C)  393 
D)  786 
E)  1179 
A)  99 
B)  197 
C)  393 
D)  786 
E)  1179

Question 3

If white light is incident on a diffraction grating:

Accepted Answer

A)  the first order lines for all visible wavelengths occur at smaller diffraction angles than any of the second order lines 
B)  some first order lines overlap the second order lines if the ruling separation is small but do not if it is large 
C)  some first order lines overlap second order lines if the ruling separation is large but do not if it is small 
D)  some first order lines overlap second order lines no matter what the ruling separation 
E)  first and second order lines have the same range of diffraction angles 
A)  the first order lines for all visible wavelengths occur at smaller diffraction angles than any of the second order lines 
B)  some first order lines overlap the second order lines if the ruling separation is small but do not if it is large 
C)  some first order lines overlap second order lines if the ruling separation is large but do not if it is small 
D)  some first order lines overlap second order lines no matter what the ruling separation 
E)  first and second order lines have the same range of diffraction angles

Question 4

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 5

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?

Accepted Answer

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

Question 6

The rainbow seen after a rain shower is caused by:

Accepted Answer

A)  diffraction 
B)  interference 
C)  refraction 
D)  polarization 
E)  absorption 
A)  diffraction 
B)  interference 
C)  refraction 
D)  polarization 
E)  absorption

Question 7

The resolving power of a telescope can be increased by:

Accepted Answer

A)  increasing the objective focal length and decreasing the eyepiece focal length 
B)  increasing the lens diameters 
C)  decreasing the lens diameters 
D)  inserting a correction lens between objective and eyepiece 
E)  none of the above 
A)  increasing the objective focal length and decreasing the eyepiece focal length 
B)  increasing the lens diameters 
C)  decreasing the lens diameters 
D)  inserting a correction lens between objective and eyepiece 
E)  none of the above

Question 8

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)?

Accepted Answer

A)  $\lambda$/2 
B)  $\lambda$ 
C)  3$\lambda$/2 
D)  2$\lambda$ 
E)  5$\lambda$/2 
A)  $\lambda$/2 
B)  $\lambda$ 
C)  3$\lambda$/2 
D)  2$\lambda$ 
E)  5$\lambda$/2

Question 9

A diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength $\lambda$. If $\lambda$ is increased and no other changes are made:

Accepted Answer

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 of the pattern 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 
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 of the pattern 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

Question 10

A light beam incident on a diffraction grating consists of waves with two different wavelengths. The separation of the two first order lines is great if:

Accepted Answer

A)  the dispersion is great 
B)  the resolution is great 
C)  the dispersion is small 
D)  the resolution is small 
E)  none of the above (line separation does not depend on either dispersion or resolution) 
A)  the dispersion is great 
B)  the resolution is great 
C)  the dispersion is small 
D)  the resolution is small 
E)  none of the above (line separation does not depend on either dispersion or resolution)

Question 11

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

Accepted Answer

A)  slightly more than 3$\lambda$/2a 
B)  slightly less than 3$\lambda$/2a 
C)  exactly 3$\lambda$/2a 
D)  exactly$\lambda$/2a 
E)  very nearly $\lambda$/2a 
A)  slightly more than 3$\lambda$/2a 
B)  slightly less than 3$\lambda$/2a 
C)  exactly 3$\lambda$/2a 
D)  exactly$\lambda$/2a 
E)  very nearly $\lambda$/2a

Question 12

When 450-nm light is incident normally on a certain double-slit system the number of interference maxima within the central diffraction maximum is 5. When 900-nm light is incident on the same slit system the number is:

Accepted Answer

A)  2 
B)  3 
C)  5 
D)  9 
E)  10 
A)  2 
B)  3 
C)  5 
D)  9 
E)  10

Question 13

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 14

Two slits of width a and separation d are illuminated by a beam of light of wavelength$\lambda$. The separation of the interference fringes on a screen a distance D away is:

Accepted Answer

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

Question 15

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 16

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 17

In a double-slit diffraction experiment the number of interference fringes within the central diffraction maximum can be increased by:

Accepted Answer

A)  increasing the wavelength 
B)  decreasing the wavelength 
C)  increasing the slit separation 
D)  decreasing the slit width 
E)  increasing the slit width 
A)  increasing the wavelength 
B)  decreasing the wavelength 
C)  increasing the slit separation 
D)  decreasing the slit width 
E)  increasing the slit width

Question 18

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$\degree$ angle. What is the wavelength, in nm, of the incident light?

Accepted Answer

A)  300 
B)  400 
C)  500 
D)  600 
E)  1000 
A)  300 
B)  400 
C)  500 
D)  600 
E)  1000

Question 19

A parallel beam of monochromatic light is incident on a slit of width 2 cm. The light passing through the slit falls on a screen 2 m away. As the slit width is decreased:

Accepted Answer

A)  the width of the pattern on the screen continuously decreases 
B)  the width of the pattern on the screen at first decreases but then increases 
C)  the width of the pattern on the screen increases and then decreases 
D)  the width of the pattern on the screen remains the same 
E)  the pattern on the screen changes color going from red to blue 
A)  the width of the pattern on the screen continuously decreases 
B)  the width of the pattern on the screen at first decreases but then increases 
C)  the width of the pattern on the screen increases and then decreases 
D)  the width of the pattern on the screen remains the same 
E)  the pattern on the screen changes color going from red to blue

Question 20

600-nm light is incident on a defraction 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$\degree$

Exam 36: Diffraction

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:

What is the minimum number of slits required in a deffraction grating to just resolve light with wavelengths of 471.0 nm and 471.6 nm?

If white light is incident on a diffraction grating:

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:

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?

The rainbow seen after a rain shower is caused by:

The resolving power of a telescope can be increased by:

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 diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength λ\lambdaλ . If λ\lambdaλ is increased and no other changes are made:

A light beam incident on a diffraction grating consists of waves with two different wavelengths. The separation of the two first order lines is great if:

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

When 450-nm light is incident normally on a certain double-slit system the number of interference maxima within the central diffraction maximum is 5. When 900-nm light is incident on the same slit system the number is:

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:

Two slits of width a and separation d are illuminated by a beam of light of wavelength λ\lambdaλ . The separation of the interference fringes on a screen a distance D away is:

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:

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

In a double-slit diffraction experiment the number of interference fringes within the central diffraction maximum can be increased by:

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 °\degree° angle. What is the wavelength, in nm, of the incident light?

A parallel beam of monochromatic light is incident on a slit of width 2 cm. The light passing through the slit falls on a screen 2 m away. As the slit width is decreased:

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

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

A diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength $\lambda$ . If $\lambda$ is increased and no other changes are made:

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

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

Two slits of width a and separation d are illuminated by a beam of light of wavelength $\lambda$ . The separation of the interference fringes on a screen a distance D away is:

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 $\degree$ angle. What is the wavelength, in nm, of the incident light?

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