Question 1

Which of the following is true for Bragg diffraction but not for diffraction from a grating?

Accepted Answer

A) Two different wavelengths may be used 
B) For a given wavelength, a maximum may exist in several directions 
C) Long waves are deviated more than short ones 
D) There is only one grating spacing 
E) Maxima occur only for particular angles of incidence 
A) Two different wavelengths may be used 
B) For a given wavelength, a maximum may exist in several directions 
C) Long waves are deviated more than short ones 
D) There is only one grating spacing 
E) Maxima occur only for particular angles of incidence

Question 2

The diagram shows a single slit with the direction to a point P on a distant screen (not 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 3

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 4

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°.The diffraction angle for the second order line is:

Accepted Answer

A) 25° 
B) 42° 
C) 50° 
D) 58° 
E) 75° 
A) 25° 
B) 42° 
C) 50° 
D) 58° 
E) 75°

Question 5

X rays are:

Accepted Answer

A) electromagnetic waves 
B) negatively charged ions 
C) rapidly moving electrons 
D) rapidly moving protons 
E) rapidly moving neutrons 
A) electromagnetic waves 
B) negatively charged ions 
C) rapidly moving electrons 
D) rapidly moving protons 
E) rapidly moving neutrons

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

Sound differs from light in that sound:

Accepted Answer

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 
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

Question 8

Radio waves are readily diffracted around buildings whereas light waves are negligibly diffracted around buildings.This is because radio waves:

Accepted Answer

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) 
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)

Question 9

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 10

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

Question 11

For a certain multiple-slit barrier the slit separation is 4 times the slit width.For this system:

Accepted Answer

A) the orders of the lines that appear are all multiples of 4 
B) the orders of the lines that appear are all multiples of 2 
C) the orders of the missing lines are all multiples of 4 
D) the orders of the missing lines are all multiples of 2 
E) none of the above are true 
A) the orders of the lines that appear are all multiples of 4 
B) the orders of the lines that appear are all multiples of 2 
C) the orders of the missing lines are all multiples of 4 
D) the orders of the missing lines are all multiples of 2 
E) none of the above are true

Question 12

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 13

A person with her eye relaxed looks through a diffraction grating at a distant monochromatic point source of light.The slits of the grating are vertical.She sees:

Accepted Answer

A) one point of light 
B) a hazy horizontal strip of light of the same color as the source 
C) a hazy strip of light varying from violet to red 
D) a sequence of horizontal points of light 
E) a sequence of closely spaced vertical lines 
A) one point of light 
B) a hazy horizontal strip of light of the same color as the source 
C) a hazy strip of light varying from violet to red 
D) a sequence of horizontal points of light 
E) a sequence of closely spaced vertical lines

Question 14

At a bright diffraction line phasors associated with waves from the slits of a multiple-slit barrier:

Accepted Answer

A) are aligned 
B) form a closed polygon 
C) form a polygon with several sides missing 
D) are parallel but adjacent phasors point in opposite directions 
E) form the arc of a circle 
A) are aligned 
B) form a closed polygon 
C) form a polygon with several sides missing 
D) are parallel but adjacent phasors point in opposite directions 
E) form the arc of a circle

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

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 17

At the second minimum adjacent to the central maximum of a single-slit diffraction pattern the Huygens wavelet from the top of the slit is 180 ° out of phase with the wavelet from:

Accepted Answer

A) a point one-fourth of the slit width from the top 
B) the midpoint of the slit 
C) a point one-fourth of the slit width from the bottom of the slit 
D) the bottom of the slit 
E) none of these 
A) a point one-fourth of the slit width from the top 
B) the midpoint of the slit 
C) a point one-fourth of the slit width from the bottom of the slit 
D) the bottom of the slit 
E) none of these

Question 18

A diffraction pattern is produced on a viewing screen by illuminating a long narrow slit with light of wavelength $\lambda$.If the slit width is decreased 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 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 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 19

If we increase the wavelength of the light used to form a double-slit diffraction pattern:

Accepted Answer

A) the width of the central diffraction peak increases and the number of bright fringes within the peak increases 
B) the width of the central diffraction peak increases and the number of bright fringes within the peak decreases 
C) the width of the central diffraction peak decreases and the number of bright fringes within the peak increases 
D) the width of the central diffraction peak decreases and the number of bright fringes within the peak decreases 
E) the width of the central diffraction peak increases and the number of bright fringes within the peak stays the same 
A) the width of the central diffraction peak increases and the number of bright fringes within the peak increases 
B) the width of the central diffraction peak increases and the number of bright fringes within the peak decreases 
C) the width of the central diffraction peak decreases and the number of bright fringes within the peak increases 
D) the width of the central diffraction peak decreases and the number of bright fringes within the peak decreases 
E) the width of the central diffraction peak increases and the number of bright fringes within the peak stays the same

Question 20

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 width of the pattern on the screen continuously increases 
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 width of the pattern on the screen continuously increases

Exam 36: Diffraction

Which of the following is true for Bragg diffraction but not for diffraction from a grating?

The diagram shows a single slit with the direction to a point P on a distant screen (not 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)?

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:

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°.The diffraction angle for the second order line is:

X rays are:

The rainbow seen after a rain shower is caused by:

Sound differs from light in that sound:

Radio waves are readily diffracted around buildings whereas light waves are negligibly diffracted around buildings.This is because radio waves:

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

The resolving power R of a grating can have units:

For a certain multiple-slit barrier the slit separation is 4 times the slit width.For this system:

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

A person with her eye relaxed looks through a diffraction grating at a distant monochromatic point source of light.The slits of the grating are vertical.She sees:

At a bright diffraction line phasors associated with waves from the slits of a multiple-slit barrier:

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?

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 second minimum adjacent to the central maximum of a single-slit diffraction pattern the Huygens wavelet from the top of the slit is 180 ° out of phase with the wavelet from:

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

If we increase the wavelength of the light used to form a double-slit diffraction pattern:

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:

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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:

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