Deck 25: Reflection and Refraction of Light

Question 1

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

Answer 1

4.4

Question 2

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 $\degree$ ,what is the angle of refraction into the air?

A)20 $\degree$
B)30 $\degree$
C)38 $\degree$
D)69 $\degree$
E)26 $\degree$

Answer 2

30 $\degree$

Question 3

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

Answer 3

0.932

Question 4

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

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

Question 5

Two mirrors are at right angles to one another.If an object is placed near the mirrors,what is the largest number of images that would be seen in the mirrors?

A)3
B)2
C)4
D)5
E)6

Question 6

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

A)21 $\degree$
B)30 $\degree$
C)38 $\degree$
D)69 $\degree$
E)71 $\degree$

Question 7

A person in a boat sees a fish in the water (n = 1.33),the light rays making an angle of 40 $\degree$ 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 8

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) $n ^ { \prime } = n \tan \theta _ { \text {mrcident } }$ .
B) $n ^ { \prime } = n \cot \theta _ { \text {mrcident } }$ .
C) $n ^ { \prime } = n \frac { \sin \theta _ { \text {indident } } } { \sin \theta _ { \text {reflection } } }$ .
D) $n ^ { \prime } = n \frac { \sin \theta _ { \text {reflection } } } { \sin \theta _ { \text {reflection } } }$ .
E) $n ^ { \prime } = n \sec \theta _ { \text {indident } }$ .

Question 9

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

A)20 $\degree$
B)60 $\degree$
C)32 $\degree$
D)64 $\degree$
E)15 $\degree$

Question 10

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 $\degree$ ,what is the angle of refraction into the carbon tetrachloride?

A)58 $\degree$
B)69 $\degree$
C)37 $\degree$
D)20 $\degree$
E)75 $\degree$

Question 11

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

A)80 $\degree$
B)40 $\degree$
C)20 $\degree$
D)60 $\degree$
E)30 $\degree$

Question 12

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? (n_water = 1.33. )

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

Question 13

Two mirrors are at right angles to one another.A light ray is incident on the first at an angle of 30 $\degree$ with respect to the normal to the surface.What is the angle of reflection from the second surface?

A)30 $\degree$
B)60 $\degree$
C)45 $\degree$
D)53 $\degree$
E)75 $\degree$

Question 14

When light scatters from a rough surface,the law $\theta _ { 1 } ^ { \prime } = \theta _ { 1 }$

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 15

The angle between two plane mirrors that meet at one edge is 45 $\degree$ .The change in direction of a ray that strikes the first mirror at a 60 $\degree$ angle of incidence when that ray reflects from the second mirror is

A)0 $\degree$ .
B)45 $\degree$
C)90 $\degree$
D)150 $\degree$
E)270 $\degree$

Question 16

A diver shines light up to the surface of a flat glass-bottomed boat at an angle of 30 $\degree$ 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 17

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface.The edges of the two mirrors meet at a 30 $\degree$ angle.A light ray that approaches mirror 1 is parallel to mirror 2.The angle of reflection of that ray from mirror 1 is

A)0 $\degree$ .
B)30 $\degree$ .
C)60 $\degree$ .
D)90 $\degree$ .
E)120 $\degree$ .

Question 18

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 19

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface.A light ray that reflects from mirror 1 at angle $\theta$ _M1 then strikes the second mirror and reflects at $\theta$ _M2 such that the angle between the ray reaching mirror 1 and the ray leaving mirror 2 is 180 $\degree$ .The angle between the two mirrors is

A)0 $\degree$ .
B)45 $\degree$ .
C)90 $\degree$ .
D)150 $\degree$ .
E)235 $\degree$ .

Question 20

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface.The edges of the two mirrors meet at a 30 $\degree$ angle.A light ray that enters parallel to mirror 2 reflects from mirror 1 and then from mirror 2.The angle of reflection of that ray from mirror 2 is

A)0 $\degree$ .
B)30 $\degree$ .
C)60 $\degree$ .
D)90 $\degree$ .
E)120 $\degree$ .

Question 21

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 n_ice = 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 22

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 23

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 $\degree$
B)41.2 $\degree$
C)51.1 $\degree$
D)58.7 $\degree$
E)49.8 $\degree$

Question 24

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 25

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

Question 26

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 $\degree$ ,what are the underwater angles of refraction for the blue and red components of the light?

Question 27

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 28

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 $\degree$
B)78 $\degree$
C)66 $\degree$
D)58 $\degree$
E)43 $\degree$

Question 29

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 30

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 $\degree$ ,what is the angle of refraction?

Question 31

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 $\degree$
B)88 $\degree$
C)68 $\degree$
D)49 $\degree$
E)the critical angle is undefined

Question 32

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 33

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 34

A light ray strikes a hexagonal ice crystal floating in the air at a 30 $\degree$ 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 n_ice = 1.30.Which outgoing ray is the correct one?

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