Question 1

Which of the following best describes the greatest known value for index of refraction?

Accepted Answer

A)  1.5 
B)  just less than 2 
C)  2 
D)  a value greater than 2 but not greater than 3 
E)  a value greater than 3 
A)  1.5 
B)  just less than 2 
C)  2 
D)  a value greater than 2 but not greater than 3 
E)  a value greater than 3

Question 2

According to Huygens's principle, every point on a wave front acts as a source of a new waves of what kind?

Accepted Answer

A)  transverse 
B)  spherical 
C)  longitudinal 
D)  sinusoidal 
E)  plane 
A)  transverse 
B)  spherical 
C)  longitudinal 
D)  sinusoidal 
E)  plane

Question 3

What is the critical angle for diamond (n = 2.42) in air?

Accepted Answer

A)  2.42° 
B)  67.5° 
C)  65.6° 
D)  24.4° 
E)  37.1° 
A)  2.42° 
B)  67.5° 
C)  65.6° 
D)  24.4° 
E)  37.1°

Question 4

A concave mirror has an object placed 40 cm in front of it. An image forms 60 cm in front of the mirror. What is the focal length of the mirror?

Accepted Answer

A)  60 cm 
B)  120 cm 
C)  −120 cm 
D)  100 cm 
E)  24 cm 
A)  60 cm 
B)  120 cm 
C)  −120 cm 
D)  100 cm 
E)  24 cm

Question 5

When total internal reflection happens at a glass-air interface

Accepted Answer

A)  half the light is refracted. 
B)  half the light is reflected. 
C)  light hits the interface from the air side. 
D)  light hits the interface from the glass side. 
E)  the law of reflection ceases to hold. 
A)  half the light is refracted. 
B)  half the light is reflected. 
C)  light hits the interface from the air side. 
D)  light hits the interface from the glass side. 
E)  the law of reflection ceases to hold.

Question 6

A ray of light enters an equilateral prism made of material with n = 1.45 at an angle of incidence θ. The internally refracted ray is parallel to the base of the prism. What is the angle of refraction for the ray leaving the prism?

Accepted Answer

A)  46.5° 
B)  30.0° 
C)  20.2° 
D)  15.7° 
E)  the ray won't leave the prism 
A)  46.5° 
B)  30.0° 
C)  20.2° 
D)  15.7° 
E)  the ray won't leave the prism

Question 7

A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. What are the size and orientation of the image?

Accepted Answer

A)  4.0 cm, inverted 
B)  4.0 cm, upright 
C)  8.9 cm, inverted 
D)  8.9 cm, upright 
E)  25 cm, upright 
A)  4.0 cm, inverted 
B)  4.0 cm, upright 
C)  8.9 cm, inverted 
D)  8.9 cm, upright 
E)  25 cm, upright

Question 8

A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. Where will the image be formed?

Accepted Answer

A)  2.5 cm behind the lens 
B)  5.6 cm behind the lens 
C)  5.6 cm in front of the lens 
D)  50 cm behind the lens 
E)  50 cm in front of the lens 
A)  2.5 cm behind the lens 
B)  5.6 cm behind the lens 
C)  5.6 cm in front of the lens 
D)  50 cm behind the lens 
E)  50 cm in front of the lens

Question 9

The image of a real object formed by a diverging lens is always

Accepted Answer

A)  real. 
B)  inverted. 
C)  larger than the object. 
D)  virtual. 
A)  real. 
B)  inverted. 
C)  larger than the object. 
D)  virtual.

Question 10

Of the following distances, which is the closest an object can be to a lens of focal length f and still produce a real image? (Note this is not the smallest possible distance, just the smallest of the provided choices.)

Accepted Answer

A)  3f 
B)  2f 
C)  1.2f 
D)  0.8f 
E)  0.49f 
A)  3f 
B)  2f 
C)  1.2f 
D)  0.8f 
E)  0.49f

Question 11

A 25 cm focal length mirror has a 3.0 cm tall object placed 20 cm in front of it. Where is the image, and is it real or virtual?

Accepted Answer

A)  5.0 cm behind the mirror, virtual 
B)  11 cm in front of the mirror, real 
C)  100 cm in front of the mirror, real 
D)  100 cm behind the mirror, virtual 
E)  45 cm behind the mirror, virtual 
A)  5.0 cm behind the mirror, virtual 
B)  11 cm in front of the mirror, real 
C)  100 cm in front of the mirror, real 
D)  100 cm behind the mirror, virtual 
E)  45 cm behind the mirror, virtual

Question 12

When a light ray in air enters glass with index of refraction 1.60, what is the greatest angle of refraction that can occur?

Accepted Answer

A)  90.0° 
B)  56.2° 
C)  52.2° 
D)  38.7° 
E)  0.0° 
A)  90.0° 
B)  56.2° 
C)  52.2° 
D)  38.7° 
E)  0.0°

Question 13

An innovative physics professor conducts laboratory exercises in the college swimming pool. The professor places a submersible laser under water (n = 1.33) and aims the beam horizontally toward the vertically oriented transparent polycarbonate side wall of the pool. The laser is shone on the pool wall at an angle of incidence of 42 degrees with respect to the normal, and at that angle the reflected ray is found to be completely polarized. What is the index of refraction of the polycarbonate side wall?

Accepted Answer

A)  1.11 
B)  1.28 
C)  1.20 
D)  1.48 
A)  1.11 
B)  1.28 
C)  1.20 
D)  1.48

Question 14

A thin lens of focal length −12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. What are the size and orientation of the image?

Accepted Answer

A)  4.0 cm, inverted 
B)  4.0 cm, upright 
C)  2.8 cm, inverted 
D)  2.8 cm, upright 
E)  100 cm, inverted 
A)  4.0 cm, inverted 
B)  4.0 cm, upright 
C)  2.8 cm, inverted 
D)  2.8 cm, upright 
E)  100 cm, inverted

Question 15

A ray of light enters a pane of glass with an angle of incidence of 37°. The index of refraction of the glass is 1.48. What is the angle of incidence as the ray reaches the glass-air interface on the far side of the pane coming from inside the glass?

Accepted Answer

A)  21° 
B)  24° 
C)  53° 
D)  37° 
E)  16° 
A)  21° 
B)  24° 
C)  53° 
D)  37° 
E)  16°

Question 16

A 6.0 cm tall object is placed 20 cm in front of a convex mirror with focal length −100 cm. What is the size of the image formed?

Accepted Answer

A)  5.0 cm 
B)  7.2 cm 
C)  7.5 cm 
D)  30 cm 
E)  12 cm 
A)  5.0 cm 
B)  7.2 cm 
C)  7.5 cm 
D)  30 cm 
E)  12 cm

Question 17

When a real object is reflected in a plane mirror, the image is always

Accepted Answer

A)  virtual. 
B)  real. 
C)  inverted. 
D)  None of these 
A)  virtual. 
B)  real. 
C)  inverted. 
D)  None of these

Exam 23: Reflection and Refraction of Light

Which of the following best describes the greatest known value for index of refraction?

According to Huygens's principle, every point on a wave front acts as a source of a new waves of what kind?

What is the critical angle for diamond (n = 2.42) in air?

A concave mirror has an object placed 40 cm in front of it. An image forms 60 cm in front of the mirror. What is the focal length of the mirror?

When total internal reflection happens at a glass-air interface

A ray of light enters an equilateral prism made of material with n = 1.45 at an angle of incidence θ. The internally refracted ray is parallel to the base of the prism. What is the angle of refraction for the ray leaving the prism?

A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. What are the size and orientation of the image?

A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. Where will the image be formed?

The image of a real object formed by a diverging lens is always

Of the following distances, which is the closest an object can be to a lens of focal length f and still produce a real image? (Note this is not the smallest possible distance, just the smallest of the provided choices.)

A 25 cm focal length mirror has a 3.0 cm tall object placed 20 cm in front of it. Where is the image, and is it real or virtual?

When a light ray in air enters glass with index of refraction 1.60, what is the greatest angle of refraction that can occur?

A thin lens of focal length −12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. What are the size and orientation of the image?

A ray of light enters a pane of glass with an angle of incidence of 37°. The index of refraction of the glass is 1.48. What is the angle of incidence as the ray reaches the glass-air interface on the far side of the pane coming from inside the glass?

A 6.0 cm tall object is placed 20 cm in front of a convex mirror with focal length −100 cm. What is the size of the image formed?

When a real object is reflected in a plane mirror, the image is always

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