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?

Accepted Answer

When the slit separation is cut in half, the distance between adjacent maxima increases. This is because the fringe width (distance between adjacent maxima) is directly proportional to the slit separation in a double-slit experiment.

Question 2

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?

Accepted Answer

When the width of the slit in a single-slit diffraction experiment is reduced, the diffraction effects become more pronounced, leading to a wider central bright fringe. This is because the angle of diffraction increases as the slit width decreases, according to the relationship described by the diffraction formula.

Question 3

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.)

Accepted Answer

The distance between the maxima in an interference pattern is dependent on the wavelength of light used. As the wavelength decreases, the distance between the maxima decreases as well. This is due to the fact that the angles at which constructive interference occurs for each slit are dependent on the wavelength of light. Similarly, the distance between the minima also depends on the wavelength, and as the wavelength decreases, the distance between the minima also decreases. Therefore, B and E are the correct choices. A and C cannot be correct as they state that the distances stay the same, which is not true. D is incorrect as the distance between the minima actually decreases.

Question 4

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

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), hence n = c/v.

Question 5

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

Accepted Answer

To get destructive interference, the two waves must be out of phase by 180 degrees. This can be achieved if one wave travels an odd number of half-wavelengths more than the other wave. Thus, option B is the best choice.

Question 6

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

Accepted Answer

For maximum constructive interference, the two beams of coherent light must have the same phase at point P. This means that the path difference between the two beams must be a whole number of wavelengths, as this is the condition for the waves to be in phase when they arrive at P. This is because the wavelength of the waves is the distance over which the wave repeats itself, and if the two waves have completed an integer number of wavelengths by the time they reach P, they will be in phase and add constructively. If the path difference is not a whole number of wavelengths, then the waves will be out of phase and interfere destructively. Therefore, choice A is the best choice.

Question 7

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?

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 8

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

Accepted Answer

When two waves are in phase, it means that their crests and troughs are aligned with each other. In the case of light waves, this means that when the electric field of one wave is at a maximum, the electric field of the other wave is also at a maximum, and they continue to maintain this relationship over time. This results in constructive interference, where the amplitudes of the two waves add up to produce a larger amplitude.

Question 9

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.)

Accepted Answer

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

Question 10

A beam of light traveling in air strikes a glass slab at an angle of incidence less than 90°.After entering the glass slab,what does the beam of light do? (There could be more than one correct choice.)

Accepted Answer

When light travels from a less dense medium (air) to a denser medium (glass), it bends towards the normal due to a decrease in speed, which is described by Snell's Law. This bending towards the normal is why choice D is correct. Additionally, light slows down when it moves from a less dense medium to a denser medium, which makes choice E correct as well.

Question 11

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?

Accepted Answer

According to the single-slit diffraction equation, the width of the central bright spot on the screen is proportional to the slit width. If the slit width is doubled, the width of the central bright spot will also double. This is because the resulting diffraction pattern will have a smaller diffraction angle, resulting in a broader central bright spot on the screen. Therefore, the width of the central bright spot will be cut in half (or reduced by a factor of 2) if the slit width is doubled.

Question 12

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

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 13

If the diameter of a radar dish is doubled,what happens to its resolving power assuming that all other factors remain unchanged?

Accepted Answer

Resolving power is directly proportional to the diameter of the radar dish. Therefore, if the diameter is doubled, the resolving power also doubles.

Question 14

When light travels from air into water,

Accepted Answer

When light moves from air into water, its speed decreases because water is denser 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 15

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?

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 16

Given perfect lenses,what is the main reason that a telescope with a large-diameter objective lens can produce a sharper image than one with a small-diameter lens?

Accepted Answer

The answer of Given perfect lenses,what is the main reason...

Question 17

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

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), given by 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 18

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

Accepted Answer

The separation between adjacent maxima in a double-slit interference experiment is given by the equation d sinθ = mλ, where d is the slit separation, θ is the angle between the central maximum and the mth maximum, λ is the wavelength of the light, and m is an integer representing the order of the maximum. From this equation, we can see that the separation is inversely proportional to the wavelength of the light. Therefore, the separation will be greatest for the longest wavelength, which is red light.

Question 19

With what color light would you expect to be able to see the finest detail when using a microscope?

Accepted Answer

Blue light has a shorter wavelength than red or yellow light, which allows it to reveal finer details when using a microscope. This is because shorter wavelengths have higher energy and can resolve smaller structures in the sample.

Question 20

Two light sources are said to be coherent if they are

Accepted Answer

Coherence refers to the property of light waves that allows them to interfere with one another. For interference to occur, the two light sources must be of the same frequency and maintain a constant phase difference. Therefore, option B is the correct choice. Options A, C, and D are not correct as they do not include the requirement of a constant phase difference.

Quiz 24: Wave Optics