Deck 38: Refraction and Images Formed by Refraction

Question 1

The actual depth of a shallow pool 1.00 m deep is not the same as the apparent depth seen when you look straight down at the pool from above. How deep (in cm) will it appear to be? (nwater = 1.33.)

A)133
B)75.2
C)90.6
D)117
E)100

Answer 1

75.2

Question 2

Bottles of perfume sometimes have thick glass (n = 1.5) walls which give the impression the volume is larger than it really is. Assume a cylindrical bottle with an inner radius of 1.0 cm and an outer radius of 2.0 cm. What percentage of the apparent volume is the real volume?

A)95%
B)60%
C)80%
D)64%
E)75%

Answer 2

64%

Question 3

If a convex lens were made out of very thin clear plastic filled with air, and were then placed underwater where n = 1.33 and where the lens would have an effective index of refraction n = 1, the lens would act in the same way

A)as a concave mirror in air.
B)as a concave lens in air.
C)as a convex lens in air.
D)as a flat refracting surface between water and air as seen from the water side.
E)as the glasses worn by a farsighted person.

Answer 3

as a concave lens in air.

Question 4

Which ray diagram is correct? The three rays in each diagram are distinguished by different types of lines. Hint: Check the behavior of each ray as it interacts with the lens.

A)A
B)B
C)C
D)D
E)E

Question 5

A 10-cm focal length converging lens is used to magnify small newspaper print 2.0 mm high. Calculate the height of the image (in mm) for the maximum magnification for a normal eye.

A)3.5
B)7.0
C)9.2
D)12
E)2.5

Question 6

Of the possible statements that parallel rays are brought to a focus by a
1.Concave mirror,
2.Convex mirror,
3.Converging lens,
4.Diverging lens,
The correct answer is

A)1 and 2.
B)3 and 4.
C)1 and 3.
D)2 and 3.
E)2 and 4.

Question 7

A compound microscope is made with an objective lens ( = 0.90 cm) and an eyepiece ( = 1.1 cm). The lenses are separated by a distance of 10 cm. If an object is 1.0 cm in front of the objective lens, where will the final image of the eyepiece be located?

A)−30
B)−15
C)−23
D)−11
E)−9

Question 8

A compound microscope is made with an objective lens (f₀ = 0.900 cm) and an eyepiece (f_e = 1.10 cm). The lenses are separated by a distance of 10.0 cm. What is the angular magnification? (Assume the near point is 25.0 cm.)

A)−253
B)−450
C)−770
D)−980
E)−635

Question 9

An object is placed 15 cm in front of a diverging lens whose focal length is 12 cm. Where will the image be located (in cm)?

A)−6.7
B)−7.2
C)−0.15
D)−60
E)−5.0

Question 10

Which ray diagrams are correct? The three rays in each diagram are distinguished by different types of lines. Hint: Check the behavior of each ray as it interacts with the lens.

A)B and C
B)C and D
C)D and E
D)C and E
E)C, D and E

Question 11

The object in a ray diagram is perpendicular to the principal axis but does not have one end lying on the principal axis. The minimum number of rays that must be drawn in this ray diagram in order to determine the position of the image is

A)1.
B)2.
C)3.
D)4.
E)5.

Question 12

An object 20-cm high is placed 50.0 cm in front of a lens whose focal length is 5.00 cm. Where will the image be located (in cm)?

A)5.13
B)5.56
C)5.72
D)5.93
E)4.55

Question 13

A far-sighted student has a near point of 1.0 m. Calculate the focal length (in cm) of the glasses needed so the near point will be normal (25 cm).

A)72
B)25
C)33
D)100
E)−33

Question 14

An object 50-cm high is placed 1.0 m in front of a converging lens whose focal length is 1.5 m. Determine the image height (in cm).

A)77
B)150
C)52
D)17
E)83

Question 15

The image of an object beneath the surface of a medium of refractive index n > 1 is seen in air by a person looking down on the surface. This image, formed by light rays leaving the flat refractive surface, is

A)real and closer to the viewer than the object.
B)virtual and closer to the viewer than the object.
C)real and farther from the viewer than the object.
D)virtual and farther from the viewer than the object.
E)virtual and the same distance from the viewer as the object.

Question 16

A plane convex lens is made of glass (n = 1.5) with one flat surface and the other having a radius of 20 cm. What is the focal length (in cm) of the lens?

A)20
B)30
C)40
D)10
E)50

Question 17

Bottles of perfume sometimes have thick glass (n = 1.5) walls which give the impression the volume is larger than it is. Assume a cylindrical bottle has an inner radius of 1.0 cm and an outer radius of 2.0 cm. How thick (in cm) would the wall appear if you could see a mark on the inside surface?

A)0.80
B)0.51
C)0.72
D)80
E)12

Question 18

A girl is sitting on the edge of a pier with her legs dangling over the water. Her soles are 80.0 cm above the surface of the water. A boy in the water looks up at her feet and wants to touch them with a reed. (nwater = 1.333.) He will see her soles as being

A)right at the water surface.
B)53.3 cm above the water surface.
C)exactly 80.0 cm above the water surface.
D)107 cm above the water surface.
E)an infinite distance above the water surface.

Question 19

A telescope is constructed with two lenses separated by a distance of 25 cm. The focal length of the objective is 20 cm. The focal length of the eyepiece is 5 cm. Calculate the magnitude of the angular magnification of the telescope.

A)6
B)4
C)8
D)10
E)5

Question 20

The purpose of prescription glasses for a near-sighted person is to bring the apparent positions of distant objects

A)to the far point of the eye.
B)to the near point of the eye.
C)to the retina of the eye.
D)none of the above.

Question 21

A contact lens is made of plastic with an index of refraction of 1.50. The lens has an outer radius of curvature of +2.0 cm and an inner radius of curvature of +2.5 cm. What are the focal length and the power of the lens?

Question 22

A layer of ethyl alcohol (n = 1.361) is on top of water (n = 1.333). To the nearest degree, at what angle relative to the normal to the interface of the two liquids is light totally reflected?

A)78°
B)88°
C)68°
D)49°
E)the critical angle is undefined

Question 23

An aquarium contains a 5-cm layer of water (n = 1.333) floating on top of carbon tetrachloride (n = 1.461). If the angle of incidence into the water from the carbon tetrachloride is 20°, what is the angle of refraction into the air?

A)20°
B)30°
C)38°
D)69°
E)26°

Question 24

A magnifying glass has a convex lens of focal length 15 cm. At what distance from a postage stamp should you hold this lens to get a magnification of +2.0?

Question 25

A diver shines light up to the surface of a flat glass-bottomed boat at an angle of 30° relative to the normal. If the index of refraction of water and glass are 1.33 and 1.5, respectively, at what angle (in degrees) does the light leave the glass (relative to its normal)?

A)26
B)35
C)42
D)22
E)48

Question 26

An object is placed 25 cm in front of a lens of focal length 20 cm. 60 cm past the first lens is a second lens of focal length 25 cm. What is the resulting magnification of the object in this setup?

A)
B)
C)
D)
E)

Question 27

An aquarium contains a 5-cm layer of water (n = 1.33) floating on top of carbon tetrachloride (n = 1.461). If the angle of incidence into the water from the air is 30°, what is the angle of refraction into the carbon tetrachloride?

A)58°
B)69°
C)37°
D)20°
E)75°

Question 28

Light strikes a diamond (n = 2.42) immersed in glycerin (n = 1.473) at an angle of 60° relative to the normal to the surface. What is the angle of refraction?

A)20°
B)60°
C)32°
D)64°
E)15°

Question 29

Light strikes a diamond (n = 2.42) at an angle of 60° relative to the normal to the surface. What is the angle of refraction?

A)21°
B)30°
C)38°
D)69°
E)71°

Question 30

A soda straw is stuck into water at an angle of 36° to the vertical. Looking straight down, what does the angle of the submerged portion of the straw to the vertical appear to be?

Question 31

A light ray is incident on the surface of water (n = 1.33) at an angle of 60° relative to the normal to the surface. The angle of the reflected wave is

A)80°.
B)40°.
C)20°.
D)60°.
E)30°.

Question 32

The speed of light changes when it goes from ethyl alcohol (n = 1.36) to carbon tetrachloride (n = 1.46). The ratio of the speed in carbon tetrachloride to the speed in ethyl alcohol, v₂/v₁, is

A)1.99.
B)1.07.
C)0.932.
D)0.511.
E)0.760.

Question 33

A diver shines an underwater searchlight at the surface of a pond (n = 1.33). At what angle (relative to the surface) will the light be totally reflected?

A)47.3°
B)41.2°
C)51.1°
D)58.7°
E)49.8°

Question 34

Light is refracted through a diamond. If the angle of incidence is 30°, and the angle of refraction is 12°, what is the index of refraction?

A)1.3
B)2.4
C)2.6
D)1.8
E)0.4

Question 35

A person in a boat sees a fish in the water (n = 1.33), the light rays making an angle of 40° relative to the water's surface. What is the true angle (in degrees) relative to the water's surface of the same rays when beneath the surface?

A)40
B)35
C)50
D)55
E)61

Question 36

An object is placed 25 cm in front of a lens of focal length 20 cm. 60 cm past the first lens is a second lens of focal length 25 cm. How far past the 25-cm lens does the final image form?

A)20 cm
B)40 cm
C)16 cm
D)25 cm
E)47 cm

Question 37

A fish is 80 cm below the surface of a pond. What is the apparent depth (in cm) when viewed from a position almost directly above the fish? (For water, n = 1.33.)

A)50
B)60
C)40
D)70
E)110

Question 38

A light ray whose frequency is 6.00 × 1014 Hz in vacuum is incident on water (n = 1.33). The wavelength of the light after it enters the water is (in nm)

A)798.
B)500.
C)665.
D)376.
E)266.

Question 39

A person looks horizontally at the edge of a swimming pool. If its length is 5 m, and the pool is filled to the surface, to what depth (in m) could the observer see? (n for water is 1.33.)

A)3.2
B)4.4
C)2.1
D)1.0
E)0.3

Question 40

Suppose an object is placed 6.0 cm in front of a lens that has a focal length of 4.0 cm. Where is the image located? What are the magnification and the character of the image?

Question 41

A light ray strikes a hexagonal ice crystal floating in the air at a 30° angle to one face, as shown below. The hexagonal faces of the crystal are perpendicular to the plane of the page. All the rays shown are in the plane of the page, and nice = 1.30. Which outgoing ray is the correct one?

A)A
B)B
C)C
D)D
E)E

Question 42

A layer of water (n = 1.333) floats on carbon tetrachloride (n = 1.461) contained in an aquarium. To the nearest degree, what is the critical angle at the interface between the two liquids?

A)88°
B)78°
C)66°
D)58°
E)43°

Question 43

A light ray strikes a hexagonal ice crystal floating in the air perpendicular to one face, as shown below. The hexagonal faces of the crystal are perpendicular to the plane of the page. All the rays shown are in the plane of the page, and nice = 1.30. Which outgoing ray is correct when the incoming ray strikes the crystal face on the left head on?

A)A
B)B
C)C
D)D
E)E

Question 44

A monochromatic (single frequency, single wavelength) light ray in air (n = 1) enters a glass prism (n = 1.5). In the glass prism

A)both the frequency and the wavelength are the same as in air
B)the frequency is the same, but the wavelength is greater than in air.
C)the frequency is the same, but the wavelength is smaller than in air.
D)the wavelength is the same, but the frequency is greater than in air.
E)the wavelength is the same, but the frequency is smaller than in air.

Question 45

A laser beam is incident from the air at an angle of 30.00° to the vertical onto a solution of Karo syrup in water. If the beam is refracted to 19.24° to the vertical, what is the index of refraction of the syrup solution?

Question 46

When a light ray travels between any two points, the path it takes is the one that (Hint: Eliminate answers you know are wrong.)

A)covers the greatest distance.
B)follows the greatest index of refraction.
C)avoids travel in more than one medium.
D)is the mean between the longest and the shortest paths.
E)takes the least time.

Question 47

The wave front shown at the left for light in air reaches the plane boundary between air and two transparent mediums with n₁ = 1.5 and n₂ = 3.00, respectively. ​ ​
Which diagram below correctly illustrates the wave front after it has entered the two mediums at the right?
​ ​

A)A
B)B
C)C
D)D
E)E

Question 48

A layer of kerosene (n = 1.45) is floating on water (n = 1.33). For what angles of incidence at the kerosene-water interface will light be totally internally reflected within the kerosene?

Question 49

The wave front shown at the left for light in air reaches the plane surface (shown by a slanted line) that bounds a medium with n = 1.50. Which diagram below correctly shows the wave front while entering the medium at the right?

A)A
B)B
C)C
D)D
E)E

Question 50

When light scatters from a rough surface, the law

A)does not hold.
B)holds on average, with reflected light from the surface leaving in the average direction of reflection.
C)applies to each small relatively flat area of surface individually.
D)applies only when the particle aspect of light predominates.
E)applies only when the wavelength of light is greater than 800 nm but less than 2000 nm.

Question 51

When light is either reflected or refracted, the quantity that does not change in either process is its

A)direction of travel.
B)dispersion.
C)frequency.
D)speed.
E)wavelength.

Question 52

The laws of refraction and reflection are the same for sound as for light. The speed of sound in air is 340 m/s and in water it is 1510 m/s. If a sound wave approaches a plane water surface at an angle of incidence of 12.0°, what is the angle of refraction?

Question 53

A light ray is partially reflected and partially refracted at a boundary between two media, the upper one having index of refraction n, the lower one having index of refraction n', as shown in the figure. The reflected ray is perpendicular to the refracted ray when

A) .
B) .
C) .
D) .
E) .

Question 54

The index of refraction for red light in water is 1.331 and for blue light is 1.340. If a ray of white light enters the water at an angle of incidence of 83.00°, what are the underwater angles of refraction for the blue and red components of the light?