Deck 24: Wave Optics: Part A

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°

Answer 1

39°

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°

Answer 2

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

Answer 3

388 nm

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°

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

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.

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.

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.

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°

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.

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

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

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

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.

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°

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

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

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

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°

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

Question 21

A fish is 2.1 m beneath the surface of a still pond of water.At what maximum angle can the fish look toward the surface (measured with respect to the normal to the surface)in order to see a fisherman sitting on a distant bank? (for water,n = 1.333)

A) 18.6°
B) 48.6°
C) 37.2°
D) The fish will not see the fisherman at any angle.

Question 22

A ray of light is incident on the mid-point of a glass prism surface at an angle of 20° with the normal.For the glass,n = 1.60,and the prism apex angle is 40°.What is the angle of incidence at the glass-to-air surface on the side opposite where the ray exits the prism? The surfaces involved are those of the apex angle.

A) 12.3°
B) 38.0°
C) 22.7°
D) 27.7°

Question 23

A monochromatic light source emits a wavelength of 490 nm in air.When passing through a liquid,the wavelength reduces to 389 nm.What is the liquid's index of refraction?

A) 1.26
B) 1.33
C) 1.14
D) 1.49

Question 24

An underwater scuba diver sees the Sun at an apparent angle of 45.0° from the vertical.How far is the sun above the horizon? (n_water = 1.333)

A) 19.5°
B) 68.0°
C) 48.2°
D) 41.8°

Question 25

A material has an index of refraction of 1.92 for light from a 560 nm source.What is the speed of light for this wavelength within the material? (c = 3.00 × 10⁸ m/s)

A) 2.19 × 10⁸ m/s
B) 4.68 × 10⁸ m/s
C) 1.56 × 10⁸ m/s
D) 1.92 × 10⁸ m/s

Question 26

What is the angle of incidence on an air-to-glass boundary if the angle of refraction in the glass (n = 1.60)is 25°?

A) 40°
B) 25°
C) 43°
D) 16°

Question 27

A ray of light travels from a glass-to-liquid interface at an angle of 41.8°.Indices of refraction for the glass and liquid are,respectively,1.52 and 1.63.What is the angle of refraction for the ray moving through the liquid?

A) 23.2°
B) 46.0°
C) 32.3°
D) 38.4°

Question 28

A beam of light is incident upon a flat piece of glass (n = 1.50)at an angle of incidence of 60°.Part of the beam is transmitted and part is reflected.What is the angle between the reflected and transmitted rays?

A) 85°
B) 28°
C) 107°
D) 152°

Question 29

A light ray passes from air through a thin plastic slab (n = 1.3)with parallel sides.If the ray in air makes an angle of 67° with the normal after leaving the slab,what is the angle of incidence for the ray in air as it impinges upon the other side of the slab?

A) 33°
B) 67°
C) 58.5°
D) 45°

Question 30

A ray of light is incident on the mid-point of a glass prism surface at an angle of 25.0° with the normal.For the glass,n = 1.55,and the prism apex angle is 40.0°.What is the angle of refraction as the ray enters the air on the far side of the prism? The surfaces involved are those of the apex angle.

A) 39.4°
B) 46.0°
C) 22.3°
D) 14.1°

Question 31

A fiber optic cable (n = 1.40)is submerged in water (n = 1.33).What is the critical angle for light to stay inside the cable?

A) 71.8°
B) 27.6°
C) 62.5°
D) 41.8°

Question 32

An oil film floats on a water surface.The indices of refraction for water and oil,respectively,are 1.333 and 1.466.If a ray of light is incident on the air-to-oil surface at an angle of 40.0° with the normal,what is the incident angle at the oil-to-water surface?

A) 24.2°
B) 37.0°
C) 26.0°
D) 18.1°

Question 33

Three materials with n₁ < n₂ < n₃ are arranged in layers of uniform thickness.A light ray in air enters the first layer at an angle of incidence of 40° and the ray eventually exits the third layer at the refracted angle θ in air.What is the value of θ?

A) Some angle more than 40°.
B) Insufficient information to answer.
C) 40°.
D) Some angle less than 40°.

Question 34

Light in air enters a diamond (n = 2.42)at an angle of incidence of 60.0°.What is the angle of refraction inside the diamond?

A) 45.6°
B) 24.7°
C) 17.9°
D) 21.0°

Question 35

When white light disperses as it passes through a prism,which of the following colors moves at the highest speed in the prism?

A) yellow
B) red
C) blue
D) green

Question 36

An oil film floats on a water surface.The indices of refraction for water and oil,respectively,are 1.333 and 1.466.If a ray of light is incident on the air-to-oil surface at an angle of 40.0° with the normal,what is the angle of the refracted ray in the water?

A) 37.0°
B) 26.8°
C) 24.2°
D) 28.8°

Question 37

If light from a 560 nm monochromatic source in air is incident upon the surface of fused quartz (n = 1.56)at an angle of 70°,what is the wavelength of the ray refracted within the quartz?

A) 560 nm
B) 874 nm
C) 192 nm
D) 359 nm

Question 38

A certain kind of glass has n_blue = 1.650 for blue light and n_red = 1.610 for red light.If a beam of white light (containing all colors)is incident at an angle of 60.0°,what is the angle between the red and blue light inside the glass?

A) 0.45.0°
B) 0.22.3°
C) 1.81°
D) 0.882°

Question 39

A ray of light is incident on a liquid-to-glass interface at an angle of 42°.Indices of refraction for the liquid and glass are,respectively,1.63 and 1.52.What is the angle of refraction for the ray moving through the glass?

A) 23°
B) 30°
C) 46°
D) 38°

Question 40

If the wavelength of a monochromatic source is 600 nm in vacuum,what is the wavelength from the same source when it passes through a liquid where the speed of light is 2.00 × 10⁸ m/s? (c = 3.00 × 10⁸ m/s)

A) 612.5 nm
B) 671 nm
C) 400 nm
D) 392 nm

Question 41

An object placed 12 cm from a concave mirror produces a real image 8.0 cm from the mirror.If the object is now moved to a new position 15.0 cm from the mirror,where is the new image located as measured from the mirror?

A) 6.5 cm
B) 14.6 cm
C) 7.1 cm
D) 3.0 cm

Question 42

A convex mirror with a focal length of −20 cm forms an image 12 cm behind the surface.If the object height is 1.2 cm what is the image height?

A) 0.30 cm
B) 0.48 cm
C) 0.94 cm
D) 3.0 cm

Question 43

An object is placed 10 cm in front of a mirror,and an image is formed that has a magnification of 3.Which of the following statements is false?

A) The image is upright.
B) The image is virtual.
C) The focal length of the mirror is 15 cm.
D) This is the only true statement.

Question 44

A slab of plastic rests on a slab of glass.A ray of light in the plastic crosses the interface between the plastic and the glass with the result that the ray bends toward the normal.What must be true about the indices of refraction in these materials?

A) n_plastic > n_glass
B) n_plastic < n_glass
C) n_plastic = n_glass
D) More information is needed to decide the answer.

Question 45

A 4.0-cm tall object is placed along the principal axis of a thin,convex lens of 30.0-cm focal length.If the object distance is 40.0 cm,which of the following best describes the image distance and height,respectively?

A) 17.3 cm and 7.0 cm
B) 17.3 cm and 1.3 cm
C) 120 cm and 1.3 cm
D) 120 cm and 12 cm

Question 46

A slab of material 1 rests on the surface of a slab of material 2.A light ray in material 1 has an angle of incidence of 30° on the interface between the materials,while the ray in material 2 has an angle of refraction of 45°.What is the critical angle of incidence for total internal reflection for a ray of light going from material 2 to material 1?

A) 30°
B) 45°
C) In this case there is no critical angle.
D) At least one of the indices of refraction or its equivalent is needed to solve this problem.

Question 47

When the midpoint of the face of the Sun appears to be on the horizon,where is the actual midpoint from the point of view of the observer?

A) above the horizon at sunrise and below the horizon at sunset
B) on the horizon
C) below the horizon
D) above the horizon

Question 48

A woman looking in a makeup mirror sees her face at twice its actual size and right-side up.If she is 22.0 cm from the mirror,what is its focal length?

A) 44.0 cm
B) 48.3 cm
C) 18.6 cm
D) 56.0 cm

Question 49

An object is 12.0 cm from the surface of a spherical Christmas tree ornament that is 10.0 cm in diameter.What is the magnification of the image?

A) −0.500
B) −0.200
C) +0.172
D) +0.143

Question 50

An object is placed 10 cm in front of a mirror,and an image is formed that has a magnification of 2.5.Which of the following statements is true?

A) This is the only true statement.
B) The focal length of the mirror is 30 cm.
C) The image is real.
D) The image is inverted.

Question 51

If a virtual image is formed 8.00 cm along the principal axis from a convex mirror of focal length -15.0 cm,how far is the object from the mirror?

A) 30.0 cm
B) 6.00 cm
C) 3.00 cm
D) 17.1 cm

Question 52

A small underwater pool light is 1.26 m below the surface of a swimming pool.What is the radius of the circle of light on the surface,from which light emerges from the water? (n_water = 1.333).

A) 0.77 m
B) 0.57 m
C) 1.13 m
D) 1.43 m

Question 53

Two parallel beams of light in air strike the surface of a transparent material and the refracted beam 1 is closer to the normal than beam 2.Which beam is traveling at higher speed in the material,and which beam has the higher index of refraction in the material?

A) beam 1,beam 1
B) beam 1,beam 2
C) beam 2,beam 2
D) beam 2,beam 1

Question 54

If a virtual image is formed along the principal axis 15 cm from a concave mirror with the focal length 15 cm,what is the object distance from the mirror?

A) 6.0 cm
B) 10 cm
C) 30 cm
D) 7.5 cm

Question 55

If an optical system consists only of an object and a single convex mirror,

A) the image will sometimes be inverted.
B) the magnification will sometimes have an absolute value greater than 1.
C) the image distance will never be negative.
D) the image will always be virtual.

Question 56

An object is held at a distance of 18 cm from a convex mirror creating an image that is 1/6 the object size.What is the focal length of the mirror?

A) −3.6 cm
B) −18 cm
C) −6.0 cm
D) −9.0 cm

Question 57

A concave mirror forms a real image at 25.0 cm from the mirror surface along the principal axis.If the corresponding object is at a 20.0-cm distance,what is the mirror's focal length?

A) 1.43 cm
B) 16.7 cm
C) 7.14 cm
D) 11.1 cm

Question 58

In glass,which of the following colors of light travels fastest?

A) red
B) blue
C) yellow
D) All three of the above travel at the same speed.

Question 59

The magnification for a flat mirror:

A) is a function of the image distance.
B) is a function of the object distance.
C) is a function of the object and image distances.
D) is 1.

Question 60

The real image of an object is located 35.0 cm away from a concave mirror,which has a focal length of 10.0 cm.How far is the object from the mirror?

A) 40.0 cm
B) 35.0 cm
C) 14.0 cm
D) 12.9 cm

Question 61

What is the image distance of an object 1.00 m in front of a converging lens of focal length 25.0 cm?

A) +25.0 cm
B) +33.3 cm
C) +20.0 cm
D) +16.7 cm

Question 62

Which of the lens shapes given below results in a diverging lens?

A) plano concave
B) double convex
C) convex meniscus
D) None of the shapes listed will be diverging.

Question 63

Ansel places an object 30 cm from a thin,convex lens along the axis.If a real image forms at a distance of 15 cm from the lens,what is the focal length of the lens?

A) 15 cm
B) 10 cm
C) 7.5 cm
D) 30 cm

Question 64

Sally places an object 6.0 cm from a thin,convex lens along its axis.The lens has a focal length of 12 cm.What are the respective values of the image distance and magnification?

A) 12 cm and −2.0
B) -12 cm and 2.0
C) 3.0 cm and −0.50
D) −6.0 cm and −1.0

Question 65

An object is placed at a distance of 40 cm from a thin,convex lens along its axis.The lens has a focal length of 10 cm.What are the values,respectively,of the image distance and magnification?

A) 13.3 cm and −0.33
B) 13.3 cm and 0.33
C) 60 cm and 2.0
D) 60 cm and −0.50

Question 66

When light goes through two or more separated lenses,

A) the image distance of the first lens (the one nearest the object)will be positive.
B) the final image can be inverted.
C) the image distance of the first lens will be the object distance for the second lens.
D) the object distance for the second lens will be negative.

Question 67

A converging lens with two convex surfaces has a front surface with radius of curvature of 10.0 cm;the back surface has radius of curvature of 30.0 cm,and the lens is made from material with an index of refraction of 2.50.What is the focal length of the lens?

A) −13.3 cm
B) 4.44 cm
C) 5.00 cm
D) 0.250 cm

Question 68

An object,located 90 cm from a concave lens,forms an image 30 cm from the lens on the same side as the object.What is the focal length of the lens?

A) −150 cm
B) −45 cm
C) −36 cm
D) −180 cm

Question 69

An object is placed at a distance of 50 cm from a thin lens along the axis.If a real image forms at a distance of 50 cm from the lens,on the opposite side from the object,what is the focal length of the lens?

A) 25 cm
B) 22 cm
C) 200 cm
D) 90 cm

Question 70

A projector lens is needed to form an image on a screen 20 times the size of its corresponding object.The screen is located 8.0 m from the lens.What is the required focal length of the lens?

A) 0.32 m
B) 0.38 m
C) 0.73 m
D) 1.25 m

Question 71

For a converging lens with two convex surfaces,the radius of curvature for both surfaces is 20 cm.If the focal length is 10 cm,what must the index of refraction be?

A) 1.5
B) 2.5
C) 2.0
D) 3.0