Question 1

In the figure, the image is viewed on a screen and is 13.5 mm tall. What is the focal length of the lens?

Accepted Answer

A)  +14.6 cm 
B)  -14.6 cm 
C)  +20.4 cm 
D)  -89.3 cm 
E)  +124 cm 
A)  +14.6 cm 
B)  -14.6 cm 
C)  +20.4 cm 
D)  -89.3 cm 
E)  +124 cm

Question 2

In the figure, a laser positioned on a ship is used to communicate with a small two-man 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 76 m deep and has an index of refraction of 1.33. How far horizontally is the submarine from the side of the ship?

Accepted Answer

A)  84.1 m 
B)  64.1 m 
C)  104 m 
D)  74.1 m 
E)  94.1 m 
A)  84.1 m 
B)  64.1 m 
C)  104 m 
D)  74.1 m 
E)  94.1 m

Question 3

A convex spherical mirror with a radius of 50 cm has a 4.0 cm tall object placed 100 cm in front of it. What is the position of the image relative to the mirror?

Accepted Answer

A)  20 cm behind the mirror 
B)  25 cm behind the mirror 
C)  100 cm in front of the mirror 
D)  25 cm in front of the mirror 
E)  20 cm in front of the mirror 
A)  20 cm behind the mirror 
B)  25 cm behind the mirror 
C)  100 cm in front of the mirror 
D)  25 cm in front of the mirror 
E)  20 cm in front of the mirror

Question 4

An object is placed 100 cm in front of a lens of focal length 20 cm. A second lens is placed 35 cm beyond the first, this second lens having a focal length of 8.0 cm. If the height of the object is 6.0 cm, what is the height of the final image?

Accepted Answer

A)  1.5 cm 
B)  12 cm 
C)  9.0 cm 
D)  3.0 cm 
E)  6.0 cm 
A)  1.5 cm 
B)  12 cm 
C)  9.0 cm 
D)  3.0 cm 
E)  6.0 cm

Question 5

A 4.0-cm tall object is placed 50.0 cm from a diverging lens having a focal length of magnitude 25.0 cm. What are the nature and location of the image? The image is

Accepted Answer

A)  real, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
B)  virtual, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 10 cm from the lens on the side opposite the object. 
D)  virtual, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object. 
E)  real, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object. 
A)  real, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
B)  virtual, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 10 cm from the lens on the side opposite the object. 
D)  virtual, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object. 
E)  real, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object.

Question 6

A ray of light strikes a boundary between two transparent materials, and there is no transmitted ray, as shown in the figure. What can you conclude about the indices of refraction of these two materials?

Accepted Answer

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

Question 7

It is desired to project the image of an object four times its actual size using a lens of focal length 20 cm. How far from the lens should the object be placed?

Accepted Answer

A)  100 cm 
B)  80 cm 
C)  4.0 cm 
D)  25 cm 
E)  5.0 cm 
A)  100 cm 
B)  80 cm 
C)  4.0 cm 
D)  25 cm 
E)  5.0 cm

Question 8

A ray of light consisting of blue light (wavelength 480 nm) and red light (wavelength 670 nm) is incident on a thick piece of glass at 80°. What is the angular separation between the refracted red and refracted blue beams while they are in the glass? (The respective indices of refraction for the blue light and the red light are 1.4636 and 1.4561.)

Accepted Answer

A)  0.27° 
B)  0.33° 
C)  0.36° 
D)  0.46° 
E)  0.54° 
A)  0.27° 
B)  0.33° 
C)  0.36° 
D)  0.46° 
E)  0.54°

Question 9

In the figure, the radius of curvature of the curved part of the lens is 35.0 cm, and the refractive index of the lens material is 1.620. What is the focal length of the lens?

Accepted Answer

A)  +56.5 cm 
B)  -56.5 cm 
C)  +28.2 cm 
D)  +21.6 cm 
E)  -21.6 cm 
A)  +56.5 cm 
B)  -56.5 cm 
C)  +28.2 cm 
D)  +21.6 cm 
E)  -21.6 cm

Question 10

Light in air is initially traveling parallel to the face AC of an equilateral triangular prism, as shown in the figure. The prism is made of glass with an index of refraction of 1.52. If the light does not strike the face AC, what is the angle between the ray as it leaves the prism at face BC and the normal in air at that face?

Accepted Answer

A)  83° 
B)  19° 
C)  59° 
D)  27° 
E)  55° 
A)  83° 
B)  19° 
C)  59° 
D)  27° 
E)  55°

Question 11

A fish appears to be 2.00 m below the surface of a pond when viewed almost directly above by a fisherman. What is the actual depth of the fish? (nwater = 1.33)

Accepted Answer

A)  2.66 m 
B)  0.67 m 
C)  1.5 m 
D)  0.38 m 
A)  2.66 m 
B)  0.67 m 
C)  1.5 m 
D)  0.38 m

Question 12

Light consisting of a mixture of red and blue light enters a 40°, 70°, 70° prism along a line parallel to the side opposite the 40° vertex. The index of refraction of the prism material for blue light is 1.530, and for red light it is 1.525. What is the angle between the two emerging beams of light?

Accepted Answer

A)  0.5° 
B)  0.9° 
C)  0.1° 
D)  0.3° 
E)  0.7° 
A)  0.5° 
B)  0.9° 
C)  0.1° 
D)  0.3° 
E)  0.7°

Question 13

An optical fiber made of glass with an index of refraction 1.50 is coated with a plastic with index of refraction 1.30. What is the critical angle of this fiber at the glass-plastic interface?

Accepted Answer

A)  90.0° 
B)  41.8° 
C)  60.1° 
D)  50.2° 
E)  61.1° 
A)  90.0° 
B)  41.8° 
C)  60.1° 
D)  50.2° 
E)  61.1°

Question 14

Which statements are true about a VIRTUAL image? (There may be more than one correct choice.)

Accepted Answer

A)  Its location can be calculated, but it cannot be viewed directly by your eye without using auxiliary lenses. 
B)  It cannot be photographed. 
C)  It cannot be viewed on a screen. 
D)  A plane mirror always forms a virtual image. 
E)  A concave lens always forms a virtual image. 
A)  Its location can be calculated, but it cannot be viewed directly by your eye without using auxiliary lenses. 
B)  It cannot be photographed. 
C)  It cannot be viewed on a screen. 
D)  A plane mirror always forms a virtual image. 
E)  A concave lens always forms a virtual image.

Question 15

A 4.0-cm tall object is placed 60 cm away from a converging lens of focal length 30 cm. What are the nature and location of the image? The image is

Accepted Answer

A)  real, 2.5 cm tall, and 30 cm from the lens on the same side as the object. 
B)  virtual, 2.5 cm tall, and 30 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 15 cm from the lens on the side opposite the object. 
D)  virtual, 4.0 cm tall, and 60 cm from the lens on the same side as the object. 
E)  real, 4.0 cm tall, and 60 cm from the lens on the side opposite the object. 
A)  real, 2.5 cm tall, and 30 cm from the lens on the same side as the object. 
B)  virtual, 2.5 cm tall, and 30 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 15 cm from the lens on the side opposite the object. 
D)  virtual, 4.0 cm tall, and 60 cm from the lens on the same side as the object. 
E)  real, 4.0 cm tall, and 60 cm from the lens on the side opposite the object.

Question 16

A fisherman in a stream 39 cm deep looks downward into the water and sees a rock on the stream bed. How deep does the stream appear to the fisherman? The index of refraction of the water is 1.33.

Accepted Answer

A)  29 cm 
B)  52 cm 
C)  33 cm 
D)  45 cm 
A)  29 cm 
B)  52 cm 
C)  33 cm 
D)  45 cm

Question 17

A tank holds a 1.44-m thick layer of oil that floats on a 0.96-m thick layer of brine. Both liquids are clear and do not intermix. Point O is at the bottom of the tank, on a vertical axis. The indices of refraction of the oil and the brine are 1.40 and 1.52, respectively. A ray originating at O reaches the brine-oil interface at the critical angle. What is the distance of this point from the axis?

Accepted Answer

A)  1.5 m 
B)  1.7 m 
C)  1.9 m 
D)  2.1 m 
E)  2.3 m 
A)  1.5 m 
B)  1.7 m 
C)  1.9 m 
D)  2.1 m 
E)  2.3 m

Question 18

An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm. A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens. Where is the final image located?

Accepted Answer

A)  10 cm in front of the second lens 
B)  20 cm past the second lens 
C)  17 cm past the second lens 
D)  10 cm past the second lens 
E)  20 cm in front of the second lens 
A)  10 cm in front of the second lens 
B)  20 cm past the second lens 
C)  17 cm past the second lens 
D)  10 cm past the second lens 
E)  20 cm in front of the second lens

Question 19

A tank holds a 1.44-m thick layer of oil that floats on a 0.96-m thick layer of brine. Both liquids are clear and do not intermix. Point O is at the bottom of the tank, on a vertical axis. The indices of refraction of the oil and the brine are 1.40 and 1.52, respectively. A ray originating at O crosses the brine-oil interface at a point 0.60 m from the axis. The ray continues and emerges into the air above the oil. What is the angle that the ray in the air makes with the vertical?

Accepted Answer

A)  48° 
B)  51° 
C)  54° 
D)  57° 
E)  60° 
A)  48° 
B)  51° 
C)  54° 
D)  57° 
E)  60°

Question 20

A man's face is 30 cm in front of a concave spherical shaving mirror. If the image is erect and 1.5 times as large as his face, what is the radius of curvature of the mirror?

Accepted Answer

A)  40 cm 
B)  60 cm 
C)  100 cm 
D)  140 cm 
E)  180 cm 
A)  40 cm 
B)  60 cm 
C)  100 cm 
D)  140 cm 
E)  180 cm

Exam 23: Ray Optics

In the figure, the image is viewed on a screen and is 13.5 mm tall. What is the focal length of the lens?

A convex spherical mirror with a radius of 50 cm has a 4.0 cm tall object placed 100 cm in front of it. What is the position of the image relative to the mirror?

An object is placed 100 cm in front of a lens of focal length 20 cm. A second lens is placed 35 cm beyond the first, this second lens having a focal length of 8.0 cm. If the height of the object is 6.0 cm, what is the height of the final image?

A 4.0-cm tall object is placed 50.0 cm from a diverging lens having a focal length of magnitude 25.0 cm. What are the nature and location of the image? The image is

A ray of light strikes a boundary between two transparent materials, and there is no transmitted ray, as shown in the figure. What can you conclude about the indices of refraction of these two materials?

It is desired to project the image of an object four times its actual size using a lens of focal length 20 cm. How far from the lens should the object be placed?

In the figure, the radius of curvature of the curved part of the lens is 35.0 cm, and the refractive index of the lens material is 1.620. What is the focal length of the lens?

A fish appears to be 2.00 m below the surface of a pond when viewed almost directly above by a fisherman. What is the actual depth of the fish? (nwater = 1.33)

An optical fiber made of glass with an index of refraction 1.50 is coated with a plastic with index of refraction 1.30. What is the critical angle of this fiber at the glass-plastic interface?

Which statements are true about a VIRTUAL image? (There may be more than one correct choice.)

A 4.0-cm tall object is placed 60 cm away from a converging lens of focal length 30 cm. What are the nature and location of the image? The image is

A fisherman in a stream 39 cm deep looks downward into the water and sees a rock on the stream bed. How deep does the stream appear to the fisherman? The index of refraction of the water is 1.33.

An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm. A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens. Where is the final image located?

A man's face is 30 cm in front of a concave spherical shaving mirror. If the image is erect and 1.5 times as large as his face, what is the radius of curvature of the mirror?

Concepts of Motion

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Newtons Third Law

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Newtons Theory of Gravity

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A fish appears to be 2.00 m below the surface of a pond when viewed almost directly above by a fisherman. What is the actual depth of the fish? (n_water = 1.33)