Question 1

In a double-slit experiment, it is observed that the distance between adjacent maxima on a remote screen is 1.0 cm. What happens to the distance between adjacent maxima when the slit separation is cut in half?
A)It increases to 2.0 cm.
B)It increases to 4.0 cm.
C)It decreases to 0.50 cm.
D)It decreases to 0.25 cm.
E)None of these choices are correct.

Accepted Answer

The distance between adjacent maxima in a double-slit experiment is directly proportional to the slit separation. Halving the slit separation doubles the distance between maxima.

Question 2

If the index of refraction of a material is 2, this means that light travels
A)2 times as fast in air as it does in vacuum.
B)2 times as fast in the material as it does in air.
C)2 times as fast in vacuum as it does in the material.
D)2 times as fast in the material than it does in vacuum.
E)1/2 as fast in air as it does in the material.

Accepted Answer

The index of refraction (n) of a material is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the material (v), i.e., n = c/v. Therefore, if the index of refraction is 2, it means light travels 2 times as fast in vacuum as it does in the material.

Question 3

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the wavelength of the illuminating light is doubled?
A)It will be cut to one-quarter its original size.
B)It will be cut in half.
C)It will double.
D)It will become four times as large.
E)It will become eight times as large.

Accepted Answer

The width of the central bright spot in a single-slit diffraction pattern is directly proportional to the wavelength of the light used. Therefore, if the wavelength is doubled, the width of the central bright spot will also double.

Question 4

What principle is responsible for light spreading as it passes through a narrow slit?
A)refraction
B)polarization
C)diffraction
D)dispersion

Accepted Answer

Diffraction is the principle responsible for light spreading as it passes through a narrow slit. Diffraction is the bending of waves, including light waves, as they pass through an opening or around an obstacle. When light passes through a narrow slit, it diffracts and spreads out, creating an interference pattern on a screen or surface behind the slit.

Question 5

In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe in the resulting diffraction pattern?
A)It stays the same.
B)It becomes narrower.
C)It becomes wider.

Accepted Answer

When the width of the slit is reduced, the diffraction effect becomes more pronounced, causing the central bright fringe to become wider. This is because the angle of diffraction increases as the slit width decreases, according to the relationship given by the diffraction formula.

Question 6

A double-slit interference experiment is performed in the air. Later, the same apparatus is immersed in benzene (which has an index of refraction of 1.50), and the experiment is repeated. When the apparatus is in benzene, you observe that the interference fringes are
A)more closely spaced than when the apparatus is in air.
B)equally spaced as when the apparatus is in air.
C)more widely spaced than when the apparatus is in air.

Accepted Answer

The wavelength of light decreases when it moves from air into a medium with a higher index of refraction, such as benzene. This decrease in wavelength leads to more closely spaced interference fringes, as the fringe spacing is directly related to the wavelength of the light.

Question 7

What do we mean when we say that two light rays striking a screen are in phase with each other?
A)When the electric field due to one is a maximum, the electric field due to the other is also a maximum, and this relation is maintained as time passes.
B)They are traveling at the same speed.
C)They have the same wavelength.
D)They alternately reinforce and cancel each other.

Accepted Answer

When we say that two light rays striking a screen are in phase with each other, it means that the electric field due to one wave is at its maximum when the electric field due to the other wave is also at its maximum. This relation is maintained consistently as time passes, indicating that the two waves have the same wavelength and frequency. This results in constructive interference, where the two waves amplify each other's amplitude, leading to brighter regions on the screen.

Question 8

Radio waves are diffracted by large objects such as buildings, whereas light is not noticeably diffracted. Why is this?
A)Radio waves are unpolarized, whereas light is normally polarized.
B)The wavelength of light is much smaller than the wavelength of radio waves.
C)The wavelength of light is much greater than the wavelength of radio waves.
D)Radio waves are coherent and light is usually not coherent.
E)Radio waves are polarized, whereas light is usually unpolarized.

Accepted Answer

The amount of diffraction that occurs is dependent upon the ratio of the wavelength of the wave to the size of the object it encounters. The wavelength of light is much smaller than the wavelength of radio waves, so light is not noticeably diffracted by large objects like buildings, while radio waves are.

Question 9

In a double-slit interference experiment you are asked to use laser light of different wavelengths and determine the separation between adjacent maxima. You observe that this separation is greatest when you illuminate the double slit with
A)blue light.
B)green light.
C)yellow light.
D)red light.
E)The separation is the same for all wavelengths.

Accepted Answer

The separation between adjacent maxima in a double-slit interference experiment is given by the equation d sin(theta) = m lambda, where d is the slit separation, theta is the angle between the line perpendicular to the slits and the line from the slits to the maxima, m is the order of the maximum (0 is the central maximum), and lambda is the wavelength of the light. As the wavelength of the light increases, the separation between adjacent maxima also increases. Since red light has the longest wavelength among the options given, it results in the greatest separation between adjacent maxima.

Question 10

If a sheet containing a single slit is heated (without damaging it)and therefore expands, what happens to the angular location of the first-order diffraction minimum?
A)It moves toward the centerline.
B)It moves away from the centerline.
C)It doesn't change.

Accepted Answer

When the sheet containing a single slit is heated and expands, the slit width increases. As the slit width increases, the diffraction pattern becomes narrower and the diffraction minimum moves toward the centerline. Therefore, the angular location of the first-order diffraction minimum moves toward the centerline.

Question 11

If a sheet containing a single thin slit is heated (without damaging it)and therefore expands, what happens to the width of the central bright diffraction region on a distant screen?
A)It gets narrower.
B)It gets wider.
C)It doesn't change.

Accepted Answer

When the sheet containing a single thin slit expands due to heating, the width of the central bright diffraction region on a distant screen will get wider. This is because the width of the slit increases, resulting in a wider diffraction pattern.

Question 12

A light beam has speed c in vacuum and speed v in a certain plastic. The index of refraction n of this plastic is A)n = cv. B)n = (v/c)². C)n = v/c. D)n = c/v. E)n = (c/v)².

Accepted Answer

The index of refraction, n, is defined as the ratio of the speed of light in vacuum, c, to the speed of light in the medium, v, which is n = c/v.

Question 13

When light travels from air into water,
A)its velocity, wavelength and frequency all change.
B)its velocity changes, but its frequency and wavelength do not change.
C)its frequency changes, but its velocity and wavelength do not change.
D)its velocity and wavelength change, but its frequency does not change.
E)its wavelength changes, but its velocity and frequency do not change.

Accepted Answer

When light moves from air into water, its speed decreases because water has a higher refractive index than air. This change in speed also leads to a change in wavelength. However, the frequency of light remains constant because it is determined by the source of the light and does not change when light moves between mediums.

Question 14

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the slit width is doubled?
A)It will be cut to one-quarter its original size.
B)It will be cut in half.
C)It will double.
D)It will become four times as large.
E)It will become eight times as large.

Accepted Answer

The width of the central bright spot is proportional to the width of the slit. Doubling the slit width will result in a halving of the width of the central bright spot, since the sine of the angle of diffraction will be halved. Therefore, the answer is B.

Question 15

Monochromatic coherent light shines through a pair of slits. If the distance between these slits is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.)
A)The distance between the maxima stays the same.
B)The distance between the maxima decreases.
C)The distance between the minima stays the same.
D)The distance between the minima increases.
E)The distance between the maxima increases.

Accepted Answer

The answer of Monochromatic coherent light shines through a pair...

Question 16

Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum destructive interference is to occur at point P, the two beams must travel paths that differ by
A)a whole number of wavelengths.
B)an odd number of half-wavelengths.
C)a whole number of half-wavelengths.

Accepted Answer

For maximum destructive interference, the two waves must be exactly out of phase, which means that one wave must be shifted by half a wavelength (180 degrees) relative to the other. Therefore, the two beams must travel paths that differ by an odd number of half-wavelengths. Choice B is the only option that satisfies this condition.

Question 17

If a sheet containing two very thin slits is heated (without damaging it), what happens to the angular location of the first-order interference minimum?
A)It moves toward the centerline.
B)It moves away from the centerline.
C)It doesn't change.

Accepted Answer

Heating the sheet will cause it to expand, which will increase the distance between the two slits. As the distance between the slits increases, the angle of diffraction (which determines the location of the interference minimum) decreases. Therefore, the first-order interference minimum moves toward the centerline.

Question 18

Two light sources are said to be coherent if they are
A)of the same frequency.
B)of the same frequency, and maintain a constant phase difference.
C)of the same amplitude, and maintain a constant phase difference.
D)of the same frequency and amplitude.

Accepted Answer

Coherence refers to the property of light waves to maintain a constant phase relationship over time. This requires that the light waves have the same frequency and maintain a constant phase difference. Therefore, choice B is the correct answer. Choices A, C, and D do not fully describe the criteria for coherence.

Question 19

Monochromatic coherent light shines through a pair of slits. If the wavelength of the light is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.)
A)The distance between the maxima stays the same.
B)The distance between the maxima decreases.
C)The distance between the minima stays the same.
D)The distance between the minima increases.
E)The distance between the minima decreases.

Accepted Answer

The distance between the maxima and the minima is directly proportional to the wavelength of light. As wavelength decreases, the distance between the maxima and minima decreases. Therefore, choices B and E are correct. The distance between the maxima and minima does not affect the distance between the maxima or minima, so choices A and C are incorrect. The distance between the minima is indirectly proportional to the wavelength of light, so as wavelength decreases, the distance between the minima increases. Therefore, choice D is incorrect.

Question 20

Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum constructive interference is to occur at point P, the two beams must travel paths that differ by
A)a whole number of wavelengths.
B)an odd number of half-wavelengths.
C)a whole number of half-wavelengths.

Accepted Answer

For maximum constructive interference, the two beams must have a path difference that is equal to a whole number of wavelengths. This is because when the waves meet at point P, the crests of one wave should overlap with the crests of the other wave, and the troughs should overlap with the troughs. This can only happen if the waves are in phase, and the path difference between them is equal to a whole number of wavelengths.

Quiz 17: Wave Optics

In a double-slit experiment, it is observed that the distance between adjacent maxima on a remote screen is 1.0 cm. What happens to the distance between adjacent maxima when the slit separation is cut in half?

If the index of refraction of a material is 2, this means that light travels

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the wavelength of the illuminating light is doubled?

What principle is responsible for light spreading as it passes through a narrow slit?

In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe in the resulting diffraction pattern?

A double-slit interference experiment is performed in the air. Later, the same apparatus is immersed in benzene (which has an index of refraction of 1.50) , and the experiment is repeated. When the apparatus is in benzene, you observe that the interference fringes are

What do we mean when we say that two light rays striking a screen are in phase with each other?

Radio waves are diffracted by large objects such as buildings, whereas light is not noticeably diffracted. Why is this?

In a double-slit interference experiment you are asked to use laser light of different wavelengths and determine the separation between adjacent maxima. You observe that this separation is greatest when you illuminate the double slit with

If a sheet containing a single slit is heated (without damaging it) and therefore expands, what happens to the angular location of the first-order diffraction minimum?

If a sheet containing a single thin slit is heated (without damaging it) and therefore expands, what happens to the width of the central bright diffraction region on a distant screen?

A light beam has speed c in vacuum and speed v in a certain plastic. The index of refraction n of this plastic is

When light travels from air into water,

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the width of the central bright spot on the screen change if the slit width is doubled?

Monochromatic coherent light shines through a pair of slits. If the distance between these slits is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.)

Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum destructive interference is to occur at point P, the two beams must travel paths that differ by

If a sheet containing two very thin slits is heated (without damaging it) , what happens to the angular location of the first-order interference minimum?

Two light sources are said to be coherent if they are

Monochromatic coherent light shines through a pair of slits. If the wavelength of the light is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.)

Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum constructive interference is to occur at point P, the two beams must travel paths that differ by