Question 1

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

Accepted Answer

The diffraction of waves around objects is more noticeable when the wavelength of the wave is comparable to or larger than the size of the object. Since the wavelength of radio waves is much larger than that of light, radio waves can be diffracted around large objects like buildings, whereas light, with its much smaller wavelength, is not noticeably diffracted in everyday situations.

Question 2

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?

Accepted Answer

When the sheet expands, the slit width increases. According to the diffraction formula, the width of the central bright region is inversely proportional to the slit width. Therefore, as the slit width increases, the central bright region becomes wider.

Question 3

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

As the temperature increases, the wavelength of light emitted by the slits increases. This causes the first-order interference minimum to move toward the centerline.

Question 4

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

When the distance between the slits decreases, the interference pattern spreads out, meaning both the distance between the maxima (bright fringes) and the distance between the minima (dark fringes) increase.

Question 5

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

Accepted Answer

When two light rays are in phase, it means their peaks and troughs align over time, resulting in their electric fields reaching maximum and minimum values simultaneously. This synchronization ensures that their phase difference remains constant, leading to constructive interference when they meet.

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 to occur at point P, the two beams of coherent light must travel paths that differ by a whole number of wavelengths. This ensures that the peaks of one wave align with the peaks of the other wave, and the troughs align as well, resulting in the maximum amplitude increase.

Question 7

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

For maximum destructive interference to occur, the path difference between the two beams must be an odd number of half-wavelengths. This causes the waves to be out of phase by 180 degrees, leading to cancellation.

Question 8

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 affects the wavelength of the light. 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 9

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 minima and maxima in an interference pattern is directly proportional to the wavelength. Therefore, if the wavelength decreases, both the distance between the minima and the maxima will decrease.

Question 10

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

The width of the central bright spot in a single-slit diffraction pattern is inversely proportional to the slit width. Therefore, if the slit width is doubled, the width of the central bright spot will be cut in half.

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
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 12

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

Accepted Answer

Diffraction is the principle responsible for the spreading of light as it passes through a narrow slit. This phenomenon occurs when waves encounter an obstacle or a slit that is comparable in size to their wavelength, causing them to bend around the edges and spread out.

Question 13

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?

Accepted Answer

When the slit expands due to heating, the width of the slit increases. According to the formula for diffraction minima, $d\sin\theta = m\lambda$ (where $d$ is the slit width, $\theta$ is the diffraction angle, $m$ is the order of the minimum, and $\lambda$ is the wavelength of light), an increase in $d$ results in a decrease in $\sin\theta$ for a given order $m$ and wavelength $\lambda$. This means the angle $\theta$ decreases, causing the first-order diffraction minimum to move toward the centerline.

Question 14

Two light sources are said to be coherent if they are

Accepted Answer

Coherent light sources must have the same frequency and maintain a constant phase difference to produce stable interference patterns. The amplitude does not need to be the same for coherence.

Question 15

If unpolarized light of intensity I0 passes through an ideal polarizer, what is the intensity of the emerging light?

Accepted Answer

When unpolarized light passes through an ideal polarizer, its intensity is reduced to half of the original intensity, according to Malus's Law.

Question 16

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

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 17

For a beam of light, the direction of polarization is defined as

Accepted Answer

The direction of polarization for a beam of light is defined as the direction in which the electric field vibrates. This is a fundamental concept in the study of electromagnetic waves, where light is considered a transverse wave with its electric field oscillating perpendicular to the direction of propagation.

Question 18

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 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 principle of wave optics.

Question 19

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 pattern is directly proportional to the wavelength of the light used. Red light has the longest wavelength among the options given, thus it will produce the greatest separation between adjacent maxima.

Question 20

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 because the fringe spacing is directly proportional to the wavelength of the light used in the experiment.

Quiz 23: Light: Geometric Optics

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

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?

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?

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.)

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

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

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

When light travels from air into water,

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 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 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?

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?

Two light sources are said to be coherent if they are

If unpolarized light of intensity I0 passes through an ideal polarizer, what is the intensity of the emerging light?

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?

For a beam of light, the direction of polarization is defined as

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?

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 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