Deck 22: Reflection and Refraction

Question 1

As shown in the figure,a laser positioned on a ship is used to communicate with a small research submarine resting on the bottom of a lake.The laser is positioned 12 m above the surface of the water,and it strikes the water 20 m from the side of the ship.The water is 58 m deep and has an index of refraction of 1.33.How far horizontally is the submarine from the side of the ship? (Assume all numbers are accurate to three significant figures.)

A)69 m
B)49 m
C)89 m
D)59 m
E)79 m

Answer 1

A

Question 2

A thin beam of light enters a thick plastic sheet from air at an angle of 32.0° with the normal and continues in the sheet at an angle of 23.0° with the normal.What is the index of refraction of the plastic?

A)0.74
B)1.11
C)1.28
D)1.36

Answer 2

D

Question 3

A glass plate with an index of refraction is 1.57 is immersed in an oil having a refractive index of 1.40.The surface of the glass is inclined at an angle of 54° with the vertical.A horizontal light ray in the glass strikes the interface.What is the angle that the refracted ray,in the oil,makes with the horizontal?

A)11°
B)5.6°
C)8.3°
D)14°
E)17°

Answer 3

A

Question 4

Light enters air from water.The angle of refraction will be

A)greater than the angle of incidence.
B)equal to the angle of incidence.
C)less than the angle of incidence.

Question 5

An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day.A light ray from the air above enters the oil at 45° with the normal and then goes into the water.What is the angle of refraction of this ray in the water? The index of refraction for the oil is 1.15,and for water it is 1.33.

A)27°
B)32°
C)36°
D)39°

Question 6

A ray of light (ray a)in air strikes a flat piece of glass at an angle of φ₀ = 84° with respect to the normal,as shown in the figure.The index of refraction of the glass is 1.5.What is the angle θ between the reflected ray (ray b)and refracted ray (ray c)rays?

Question 7

The index of refraction for a certain material is 1.399 for red light and 1.432 for blue light.Light containing both of these colors is traveling in vacuum and strikes a flat sheet of this material.Find the angle separating the two colors in the refracted light in the sheet if the angle of incidence is 60.00°.

Question 8

A light ray in glass arrives at the glass-water interface an an angle of θ = 48° with the normal.The refracted ray in water makes an angle φ = 72° angle with the normal,as shown in the figure.The index of refraction of water is 1.33.The angle of incidence is now changed to θ = 37°.What is the new angle of refraction φ in the water?

A)50°
B)48°
C)46°
D)52°
E)54°

Question 9

A light ray in air strikes a glass plate whose index of refraction is 1.42.Some of the light reflects off the surface of the plate,but most of it enters the glass.If the angle of refraction is one-half the angle of reflection,the angle of refraction is closest to which one of the following angles?

A)45°
B)43°
C)41°
D)39°
E)37°

Question 10

Light goes from material having a refractive index of n₁ into a material with refractive index n₂.If the refracted light is bent away from the normal,what can you conclude about the indices of refraction?

A)n₁ > n₂
B)n₁ ≥ n₂
C)n₁ < n₂
D)n₁ ≤ n₂
E)n₁ = n₂

Question 11

A flashlight beam makes an angle of 60° with the plane of the surface of a calm lake before it enters the water.In the water what angle does the beam make with the plane of the surface? The index of refraction of water is 1.33.

A)0°
B)30°
C)60°
D)22°
E)68°

Question 12

Light enters glass from air.The angle of refraction will be

A)greater than the angle of incidence.
B)equal to the angle of incidence.
C)less than the angle of incidence.

Question 13

A beam of light in water (of refractive index of 1.33)enters a glass slab (of refractive index 1.50)at an angle of incidence of 60.0°.What is the angle of refraction in the glass?

A)27.5°
B)39.8°
C)60.0°
D)90.0°
E)50.2°

Question 14

A beam of light in air enters a glass slab with an index of refraction of 1.40 at an angle of incidence of 30.0°.What is the angle of refraction?

A)20.9°
B)47.5°
C)51.8°
D)30.0°
E)14.9°

Question 15

A light ray in glass arrives at the glass-water interface at an angle of θ = 48° with the normal.The refracted ray in water makes an angle θ = 61° with the normal,as shown in the figure.The index of refraction of water is 1.33.The angle of incidence is now changed to θ = 25°.What is the new angle of refraction φ in the water?

A)30°
B)56°
C)54°
D)60°
E)62°

Question 16

The index of refraction of a type of glass is 1.50,and the index of refraction of water is 1.33.If light enters water from this glass,the angle of refraction will be

A)greater than the angle of incidence.
B)equal to the angle of incidence.
C)less than the angle of incidence.

Question 17

A thin flashlight beam traveling in air strikes a glass plate at an angle of 52° with the plane of the surface of the plate.If the index of refraction of the glass is 1.4,what angle will the beam make with the normal in the glass?

A)34°
B)64°
C)26°
D)56°
E)38°

Question 18

A narrow light beam in vacuum contains light of two wavelengths,480 nm and 700 nm.It strikes a flat piece of glass at an angle of incidence of 60.000°.The index of refraction of the glass is 1.4830 at 480 nm and 1.4760 at 700 nm.Determine the angle between the two wavelengths as the light travels in the glass.

Question 19

A beam of light,traveling in air,strikes a plate of transparent material at an angle of incidence of 56.0°.It is observed that the reflected and refracted beams form an angle of 90.0°.What is the index of refraction of this material?

A)1.40
B)1.43
C)1.44
D)1.48

Question 20

The critical angle for a beam of light passing from water into air is 48.8°.This means that all light rays with an angle of incidence in the water that is greater than 48.8° will be

A)totally absorbed by the water.
B)totally reflected.
C)partially reflected and partially transmitted.
D)totally transmitted.

Question 21

A tank holds a layer of oil,of thickness T_o = 1.43 m,that floats on a layer of syrup of thickness T_s = 0.640 m,as shown in the figure.Both liquids are clear and do not mix together.A light ray,originating at the bottom of the tank at point P,crosses the oil-syrup interface at a point 0.900 m from the axis.The ray continues and arrives at the oil-air interface,2.00 m to the right of P and at the critical angle.What is the index of refraction of the oil?

A)1.64
B)1.62
C)1.60
D)1.66
E)1.68

Question 22

Lucite has an index of refraction of 1.50.What is its critical angle if it is in air?

A)1.16°
B)15°
C)41.8°
D)65.2°
E)87.4°

Question 23

Light in a transparent material that has an index of refraction of 1.333 strikes the boundary with another transparent material for which the index of refraction is 1.010.What is the critical angle for total internal reflection between these two materials?

Question 24

A tank holds a layer of oil,of thickness T_o = 1.65 m,that floats on a layer of syrup of thickness T_s = 0.830 m,as shown in the figure.Both liquids are clear and do not mix together.A light ray,originating at the bottom of the tank at point P,crosses the oil-syrup interface at a point 0.900 m from the axis.The ray continues and arrives at the oil-air interface,2.00 m to the right of P and at the critical angle.What is the index of refraction of the syrup?

A)1.36
B)1.25
C)1.94
D)1.75
E)1.54

Question 25

During the investigation of a new type of optical fiber having an index of refraction a laser beam is aimed at the flat end of a straight fiber,as shown in the figure.What is the maximum angle of incidence θ₁ if the beam is not to escape from the sides of the fiber if it is surrounded by air?

A)42.9°
B)39.8°
C)36.7°
D)33.6°
E)30.5°

Question 26

The critical angle for a substance in air is measured at 53.7°.If light enters this substance from air at 45.0° with the normal,at what angle with the normal will it continue to travel?

A)34.7°
B)45.0°
C)53.7°
D)It will not continue, but will be totally reflected.

Question 27

A scuba diver is 1.2 m beneath the surface of a still pond of water.At what angle relative to the normal at the surface must the diver shine a beam of light toward the surface in order for a person on a distant bank to be able to see it? The index of refraction for water is 1.33.

A)41°
B)48°
C)59°
D)90°
E)0°

Question 28

A light beam is traveling inside a glass block that has an index of refraction of 1.46.As this light arrives at the surface of the block,it makes an angle of 53.0° with the normal.At what angle with the normal in the air will it leave the block?

A)It will not leave.
B)59.1°
C)43.2°
D)33.2°

Question 29

A glass plate having an index of refraction is 1.66 is immersed in a certain alcohol.The surface of the glass is inclined at an angle of 44° with the vertical.When a horizontal ray in the glass strikes the interface,you observe that it is at the critical angle.What is the index of refraction of the alcohol?

A)1.15
B)1.13
C)1.11
D)1.09
E)1.17

Question 30

A ray of light in glass strikes a water-glass interface at an angle of incidence equal to one-half the critical angle for that interface.The index of refraction for water is 1.33,and for the glass it is 1.43.What angle does the refracted ray in the water make with the normal?

A)37°
B)42°
C)47°
D)32°
E)27°

Question 31

Light enters a substance from air at 30.0° to the normal.It continues within the substance at 23.0° to the normal.What is the critical angle for this substance when it is surrounded by air?

A)53°
B)51.4°
C)36.7°
D)12.6°

Question 32

A light ray enters a glass enclosed fish tank.From air it enters the glass at 20° with respect to the plane of the surface and then emerges into the water.The index for the glass is 1.50 and for water 1.33.
(a)What is the angle of refraction in the glass?
(b)What is the angle of refraction in the water?
(c)Is there any incident angle in air for which the ray will not enter the water due to total internal reflection? If so,find it.

Question 33

Light travels from crown glass,with a refractive index of 1.52,into water,having a refractive index of 1.33? The critical angle for this interface is closest to which one of the following angles?

A)42°
B)48°
C)53°
D)57°
E)61°

Question 34

An optic fiber is made of clear plastic with an index of refraction of 1.50.For what range of angles of incidence θ with the lateral surface of the fiber will light remain inside the plastic "guide" if it is surrounded by air?

A)21.1° < θ < 90°
B)23.4° < θ < 90°
C)38.3° < θ < 90°
D)40.3° < θ < 90°
E)41.8° < θ < 90°

Question 35

A ray of light traveling in air makes a 63.0° angle with respect to the normal of the surface of a liquid.It travels in the liquid at a 39.2° angle with respect to the normal.Find the critical angle for total internal reflection for this interface.

Question 36

A point source of light is positioned 20.0 m below the surface of a lake.What is the diameter of the largest circle on the surface of the water through which light can emerge into the air? The index of refraction of water is 1.33.