Deck 37: Reflection and Images Formed by Reflection

Question 1

An object 15 cm high is placed 15 cm in front of a convex mirror with a focal length of −10 cm. What is the image height (in cm)?

A)2
B)4
C)6
D)8
E)30

Answer 1

6

Question 2

A clown 2 m tall looks at himself in a full-length mirror (floor-to-ceiling). Where in the mirror must he look to see his feet?

A)1 m from the floor
B)50 cm from the floor
C)25 cm from the floor
D)at the bottom of the mirror
E)1.5 m from the floor

Answer 2

1 m from the floor

Question 3

An object is placed 15 cm in front of a concave mirror with a focal length of 30 cm. What is the magnification?

A)1
B)2
C)1/2
D)1/4
E)−2

Answer 3

2

Question 4

A magician can make a candle look as if it is burning under water by focusing light from a candle flame burning in air directly on top of an underwater candle. To do this you want to use a (Hint: eliminate those that cannot work.)

A)concave mirror farther than one focal length from the burning candle.
B)a convex mirror farther than one focal length from the burning candle.
C)a biconcave lens farther than one focal length from the burning candle.
D)a concave mirror closer than one focal length to the burning candle.
E)a convex lens closer than one focal length to the burning candle.

Question 5

​An object is placed a distance y₀ = −2f in front of a concave mirror of focal length f that is located at y = 0. An identical object is placed a distance ​y'₀ = −2f in front of a convex mirror of focal length −f that is located at y' = 0. The difference between the two image positions, y_i − y'_i, is

A)​f /2.
B)​f.
C)​4f /3.
D)​2f.
E)​8​f​ /3.

Question 6

If you stand closer to a concave mirror than a distance of one focal length, the image you see is

A)real and inverted.
B)real and upright.
C)virtual and inverted.
D)virtual and upright.
E)none of the above because you do not get an image.

Question 7

An object is placed 10 cm in front of a concave mirror with a 20-cm focal length. Determine the image location (in cm).

A)−20
B)−15
C)−10
D)−5
E)6.7

Question 8

A concave mirror has a focal length of 20 cm. What is the position (in cm) of the object if the image is upright and is two times larger than the object?

A)30
B)20
C)10
D)40
E)60

Question 9

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

A)​30°
B)​60°
C)​45°
D)​53°
E)​75°

Question 10

A concave mirror has a radius of curvature of 1.0 m. An object is placed 2.0 m in front of the mirror. Determine the location of the image (in cm).

A)130
B)83
C)67
D)150
E)200

Question 11

An object 4 cm high is placed 15 cm in front of a convex mirror with a focal length of −10 cm. What is the image position (in cm)?

A)−8
B)−4
C)−2
D)−6
E)30

Question 12

A concave mirror has a focal length of 20 cm. What is the magnification if the object and image distances are 10 cm and −20 cm, respectively?

A)1
B)2
C)1/2
D)1/4
E)−1/2

Question 13

The inhabitants of a planet in another galaxy have their eyes at the exact center of their 4.0-m-long bodies. How long must a plane mirror be for such a creature to be able to see all of its body in the mirror?

A)1.0 m
B)2.0 m
C)2.5 m
D)4.0 m
E)8.0 m

Question 14

When you stand in front of a convex mirror, the image you see is

A)real and inverted.
B)real and upright.
C)virtual and inverted.
D)virtual and upright.
E)real and inverted if your distance from the mirror is greater than two focal lengths.

Question 15

A concave mirror with a radius of curvature of 1.0 m is illuminated by a candle located on the symmetry axis 3.0 m from the mirror. Where is the image of the candle?

Question 16

A convex mirror has a focal length of −20 cm. What is the position of the resulting image (in cm) if the image is upright and four times smaller than the object?

A)−100
B)−25
C)−50
D)−15
E)−10

Question 17

A dentist uses a concave mirror (focal length 2 cm) to examine some teeth. If the distance from the object to the mirror is 1 cm, what is the magnification of the tooth?

A)6
B)1
C)4
D)2
E)1.5

Question 18

A convex mirror has a focal length of −20 cm. What is the object distance if the image distance is −10 cm?

A)10 cm
B)40 cm
C)60 cm
D)20 cm
E)30 cm

Question 19

A concave mirror has a focal length of 20 cm. What is the position (in cm) of the resulting image if the image is inverted and four times smaller than the object?

A)15
B)25
C)50
D)100
E)−15

Question 20

A concave mirror has a focal length of 20 cm. What is the magnification if the object's distance is 100 cm?

A)1/2
B)1/4
C)−2
D)4
E)−1/4

Question 21

​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° 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°.
B)30°.
C)​60°.
D)​90°.
E)​120°.

Question 22

​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 θM 1 then strikes the second mirror and reflects at θM 2 such that the angle between the ray reaching mirror 1 and the ray leaving mirror 2 is 180°. The angle between the two mirrors is

A)​0°.
B)​45°.
C)​90°.
D)​150°.
E)​235°.

Question 23

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

A)​0°.
B)​45°.
C)​90°.
D)​150°.
E)​270°.

Question 24

​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° 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°.
B)​30°.
C)​60°.
D)​90°.
E)​120°.

Question 25

​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