Question 1

A ray of light strikes a thick sheet of glass (n = 1.5)at an angle of 39° with the normal.Find the angle of the ray reflected off the glass surface with respect to the normal.
A) 56°
B) 25°
C) 46°
D) 39°

Accepted Answer

The angle of reflection is equal to the angle of incidence, so the reflected ray will also make an angle of 39° with the normal.

Question 2

Two plane mirrors make an angle of 50° with one another.A ray of light parallel to mirror #1 reflects off mirror #2 and then strikes mirror #1.What is the angle of incidence the ray makes with mirror #1?
A) 50°
B) The answer is not given.
C) 40°
D) 55°

Accepted Answer

When a ray of light reflects off a plane mirror, the angle of incidence is equal to the angle of reflection. Since the ray of light is parallel to mirror #1, it makes an angle of 50° with mirror #2. When it reflects off mirror #2, it will make the same angle with mirror #2, so the angle of reflection is also 50°. The sum of the angle of incidence and angle of reflection is equal to the angle between the two mirrors, which is 50°. Therefore, the angle of incidence is 50° - 50° = 0°. However, this is not the correct answer since the ray of light cannot hit mirror #1 at 0° incidence. To find the correct angle of incidence, we need to extend the reflected ray back to mirror #1 and draw an incident ray that is perpendicular to the reflected ray. This creates a right triangle with the angle of incidence as the angle opposite the side adjacent to the angle of 50°. Using trigonometry, we can find that this angle is approximately 40°.

Question 3

A monochromatic beam of light in air has a wavelength of 632 nm.It passes through glass (n = 1.52)and then through carbon disulfide (n = 1.63).What is its wavelength in the carbon disulfide?
A) 361 nm
B) 960 nm
C) 895 nm
D) 388 nm

Accepted Answer

D

Question 4

A corner cube is formed by three plane mirrors perpendicular to one another resulting in a retroreflector.What is the angle between the directions of an incoming ray of light and of the corresponding outgoing ray of light for this device?
A) 90°
B) 180°
C) 0°
D) 360°

Accepted Answer

The angle between the directions of an incoming ray of light and the corresponding outgoing ray of light for a corner cube (retroreflector) is 180°, as the outgoing ray is parallel but opposite in direction to the incoming ray.

Question 5

If the speed of light through an unknown liquid is measured at 1.67 × 10⁸ m/s,what is the index of refraction of this liquid? (c = 3.00 × 10⁸ m/s) A) 1.80 B) 1.67 C) 0.600 D) 1.20

Accepted Answer

The index of refraction (n) is calculated using the formula n = c/v, where c is the speed of light in a vacuum (3.00 × 10^8 m/s) and v is the speed of light in the medium (1.67 × 10^8 m/s). So, n = 3.00 × 10^8 / 1.67 × 10^8 = 1.80.

Question 6

When the reflection of an object is seen in a plane mirror,the distance from the mirror to the image depends on:
A) the distance from the object to the mirror.
B) the size of the object.
C) the distance of both the observer and the object to the mirror.
D) the wavelength of light used for viewing.

Accepted Answer

The distance from the mirror to the image depends only on the distance from the object to the mirror. This is because the angle of incidence equals the angle of reflection, and the image formed is at the same distance behind the mirror as the object is in front of it.

Question 7

A mirror lies flat on a table.A beam of light strikes the mirror with an angle of incidence or 15°,the reflected ray being to the right of the incident beam.The right edge of the mirror is then lifted so that the mirror now makes a 5° angle with the horizontal.What is the resulting angle between the incident beam and the reflected beam?
A) 25°
B) 20°
C) 35°
D) The angle is not given.

Accepted Answer

When the mirror lies flat on the table, the angle of incidence (i) equals the angle of reflection (r), resulting in the reflected beam being 15° to the right of the incident beam.

After lifting the right edge of the mirror, the angle of incidence increases to 20°, and the angle of reflection also increases to 20°, resulting in the reflected beam still being 15° to the right of the incident beam.

Therefore, the resulting angle between the incident beam and reflected beam is 20° (i + r), which corresponds to choice B.

Question 8

How large should a wall-mounted mirror be to view the upper half of one's height,h?
A) h
B) h/2
C) h/4
D) The answer is not given.

Accepted Answer

The answer of How large should a wall-mounted mirror be...

Question 9

A beam of light in air is incident at an angle of 46° to the surface of a rectangular block of clear plastic (n = 1.46).The light beam first passes through the block and re-emerges from the opposite side into air at what angle to the normal to that surface?
A) 23°
B) 59°
C) 46°
D) 30°

Accepted Answer

According to Snell's Law, the angle of incidence equals the angle of emergence when light passes through a parallel-sided block. Thus, the light re-emerges at the same angle of 46° to the normal.

Question 10

If a man wishes to use a plane mirror on a wall to view both his head and his feet as he stands in front of the mirror,the required length of the mirror:
A) depends on both the height of the man and the distance from the man to the mirror.
B) is equal to the height of the man.
C) is equal to one-half the height of the man.
D) depends on the distance the man stands from the mirror.

Accepted Answer

The required length of the mirror is equal to one-half the height of the man since the mirror shows a reflection of the man's full height, which is the distance from his head to his feet, and the mirror image is the same size as the actual object, so the mirror's length would be equal to half of the man's height.

Question 11

Which of the following best describes the image from a plane mirror?
A) virtual and magnification equal to one
B) real and magnification equal to one
C) real and magnification less than one
D) virtual and magnification greater than one

Accepted Answer

A plane mirror forms a virtual image that is the same size as the object, so the magnification is equal to one.

Question 12

You stand three feet away from a plane mirror.How far is it from you to your image?
A) 4.0 ft
B) 6.0 ft
C) 2.0 ft
D) 3.0 ft

Accepted Answer

The distance from you to the mirror is 3 feet, and the distance from the mirror to your image is also 3 feet. Therefore, the total distance from you to your image is 3 + 3 = 6 feet.

Question 13

A light ray in air is incident on an air-to-glass boundary at an angle of 30.0° and is refracted in the glass at an angle of 16.7° with the normal.Find the index of refraction of the glass.
A) 1.74
B) 1.40
C) 1.23
D) 2.13

Accepted Answer

Using Snell's law, we have:

n_air * sin(30.0°) = n_glass * sin(16.7°)

We know that n_air = 1 (since it's air)

Therefore:

n_glass = sin(30.0°)/sin(16.7°)

n_glass = 1.74

Therefore, the index of refraction of the glass is 1.74. The correct choice is A.

Question 14

When the reflection of an object is seen in a plane mirror,the image is:
A) real and upright.
B) virtual and upright.
C) real and inverted.
D) virtual and inverted.

Accepted Answer

The image seen in a plane mirror is a virtual image, as it appears to be behind the mirror and cannot be projected onto a screen. It is also upright, as it is not flipped or inverted like a real image would be.

Question 15

A ray of light strikes a thick sheet of glass (n = 1.5)at an angle of 46° with the normal.Find the angle of the refracted ray within the glass with respect to the normal.
A) 25°
B) 56°
C) 29°
D) 16°

Accepted Answer

Using Snell's law, we have sin(i)/sin(r) = n, where i is the angle of incidence and r is the angle of refraction. Rearranging, we get sin(r) = sin(i)/n. Plugging in the values, we have sin(r) = sin(46°)/1.5 = 0.507. Taking the inverse sine of this value, we get r = 29°. Therefore, the angle of the refracted ray within the glass with respect to the normal is 29°. The correct choice is C.

Question 16

A liquid has an index of refraction of 1.33.What is the speed of light through it? (c = 3.00 × 10⁸ m/s) A) 3.99 × 10⁸ m/s B) 2.26 × 10⁸ m/s C) 4.46 × 10⁸ m/s D) 2.04 × 10⁸ m/s

Accepted Answer

The speed of light in a medium is given by v = c/n, where n is the index of refraction. Therefore, the speed of light in this particular liquid is v = (3.00 × 10^8 m/s) / 1.33 = 2.26 × 10^8 m/s. The correct choice is B.

Question 17

A beam of light in air is incident on the surface of a rectangular block of clear plastic (n = 1.40).If the speed of the beam before it enters the plastic is 3.00 × 10⁸ m/s,what is its speed inside the block? A) 2.14 × 10⁸ m/s B) 2.01 × 10⁸ m/s C) 1.94 × 10⁸ m/s D) 3.00 × 10⁸ m/s

Accepted Answer

The speed of light in a material with refractive index n is given by v = c/n, where c is the speed of light in vacuum. Therefore, the speed of the beam inside the plastic block is:
v = c/n = (3.00 × 10^8 m/s) / 1.40 = 2.14 × 10^8 m/s
Thus, the correct answer is A.

Question 18

Monochromatic light hits a piece of glass.Assuming the frequency remains constant,what happens to the wavelength in the glass as the index of refraction decreases? A) decreases B) approaches 3 × 10⁸ m C) increases D) remains constant

Accepted Answer

According to Snell's law of refraction, n1*sin(theta1) = n2*sin(theta2), as the index of refraction decreases, the angle of refraction increases. Therefore, the wavelength in the glass increases, leading to a decrease in frequency.

Question 19

Light from a 560-nm monochromatic source is incident upon the surface of fused quartz (n = 1.56)at an angle of 30°.What is the angle of reflection from the surface?
A) 30°
B) 75°
C) 60°
D) 15°

Accepted Answer

The angle of reflection is equal to the angle of incidence according to the law of reflection. Therefore, the angle of reflection is 30°.

Question 20

Assuming the frequency remains constant,a monochromatic light ray is transmitted through an glass-to-air boundary,what happens to the wavelength?
A) decreases
B) approaches zero value
C) increases
D) remains unchanged

Accepted Answer

When a monochromatic light ray passes from glass to air, its speed increases because air has a lower refractive index than glass. Since the frequency remains constant and the speed of light increases, the wavelength must increase according to the relationship $v = f\lambda$, where $v$ is the speed of light, $f$ is the frequency, and $\lambda$ is the wavelength.

Quiz 24: Wave Optics: Part A

A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 39° with the normal.Find the angle of the ray reflected off the glass surface with respect to the normal.

Two plane mirrors make an angle of 50° with one another.A ray of light parallel to mirror #1 reflects off mirror #2 and then strikes mirror #1.What is the angle of incidence the ray makes with mirror #1?

A monochromatic beam of light in air has a wavelength of 632 nm.It passes through glass (n = 1.52) and then through carbon disulfide (n = 1.63) .What is its wavelength in the carbon disulfide?

A corner cube is formed by three plane mirrors perpendicular to one another resulting in a retroreflector.What is the angle between the directions of an incoming ray of light and of the corresponding outgoing ray of light for this device?

If the speed of light through an unknown liquid is measured at 1.67 × 10⁸ m/s,what is the index of refraction of this liquid? (c = 3.00 × 10⁸ m/s)

When the reflection of an object is seen in a plane mirror,the distance from the mirror to the image depends on:

How large should a wall-mounted mirror be to view the upper half of one's height,h?

A beam of light in air is incident at an angle of 46° to the surface of a rectangular block of clear plastic (n = 1.46) .The light beam first passes through the block and re-emerges from the opposite side into air at what angle to the normal to that surface?

If a man wishes to use a plane mirror on a wall to view both his head and his feet as he stands in front of the mirror,the required length of the mirror:

Which of the following best describes the image from a plane mirror?

You stand three feet away from a plane mirror.How far is it from you to your image?

A light ray in air is incident on an air-to-glass boundary at an angle of 30.0° and is refracted in the glass at an angle of 16.7° with the normal.Find the index of refraction of the glass.

When the reflection of an object is seen in a plane mirror,the image is:

A ray of light strikes a thick sheet of glass (n = 1.5) at an angle of 46° with the normal.Find the angle of the refracted ray within the glass with respect to the normal.

A liquid has an index of refraction of 1.33.What is the speed of light through it? (c = 3.00 × 10⁸ m/s)

A beam of light in air is incident on the surface of a rectangular block of clear plastic (n = 1.40) .If the speed of the beam before it enters the plastic is 3.00 × 10⁸ m/s,what is its speed inside the block?

Monochromatic light hits a piece of glass.Assuming the frequency remains constant,what happens to the wavelength in the glass as the index of refraction decreases?

Light from a 560-nm monochromatic source is incident upon the surface of fused quartz (n = 1.56) at an angle of 30°.What is the angle of reflection from the surface?

Assuming the frequency remains constant,a monochromatic light ray is transmitted through an glass-to-air boundary,what happens to the wavelength?