Chapter 28: Reflection and Refraction

Question 1

Light will almost always travel from one place to another along a path of least: a) distance; b) time; c) effort; d) expense; e) complication.

Answer 1

b) time.

Question 2

The amount of light reflected from the front surface of a common windowpane is about: a) 4 percent; b) 8 percent; c) 40 percent; d) 92 percent; e) 96 percent.

Answer 2

a) 4 percent.

Question 3

The shortest plane mirror in which you can see your entire image is

Answer 3

half your height.

Question 4

A mirage is a result of atmospheric

Answer 4

refraction.

Question 5

The average speed of light is greatest in: a) red glass; b) orange glass; c) green glass; d) blue glass; e) is the same in all of these.

Answer 5

a) red glass.

Question 6

The Law of Reflection says that: a) changes in latitude equal changes in attitude; b) the angle of incidence equals the angle of reflection; c) the speed of light in a vacuum x n = the speed of light in the material; d) the distance to the object equals the distance to the virtual image; e) the actual light path equals the apparent light path.

Answer 6

b) the angle of incidence equals the angle of reflection.

Question 7

A single raindrop illuminated by sunshine disperses: a) a single color; b) either low, middle, or high-frequency colors in most cases; c) all the colors of the rainbow.

Answer 7

c) all the colors of the rainbow.

Question 8

Diffuse reflection occurs when the size of surface irregularities is: a) small compared to the wavelength of the light used; b) large compared to the wavelength of the light used; c) microscopic.

Answer 8

b) large compared to the wavelength of the light used.

Question 9

If you walk towards a mirror at a certain speed, the relative speed between you and your image is: a) half your speed; b) your speed; c) twice your speed; d) none of these.

Answer 9

c) twice your speed.

Question 10

Light travels fastest in

Answer 10

a vacuum.

Question 11

Different colors are dispersed by a prism because different colors in the prism have different: a) frequencies; b) speeds; c) directions; d) energies.

Answer 11

b) speeds.

Question 12

Refraction causes the bottom of a swimming pool to appear: a) farther down than it actually is; b) closer to the surface than it actually is; c) neither.

Answer 12

b) closer to the surface than it actually is.

Question 13

As a light ray enters and exits a water-air interface, it: a) always bends toward the normal; b) always bends away from the normal; c) sometimes bends towards the normal, sometimes bends away; d) does not bend.

Answer 13

c) sometimes bends towards the normal, sometimes bends away.

Question 14

When light reflects from a surface, there is a change in its: a) frequency; b) wavelength; c) speed; d) all of these; e) none of these

Answer 14

e) none of these

Question 15

Object and image for a plane mirror lie: a) along the same plane; b) equal distances from the mirror; c) at right angles to each other. d) all of these; e) none of these.

Answer 15

b) equal distances from the mirror.

Question 16

Your vision is sharpest when your pupil is: a) dilated; b) constricted; c) same either way.

Answer 16

b) constricted.

Question 17

Light takes the ________ path in going from one place to another. ​

Answer 17

quickest;

Fermat’s principle of least time.

Question 18

We say light is _________ when it is returned into the medium from which it came.

Answer 18

reflected;

The process is reflection.​

Question 19

The angle of reflection equals the angle of

Answer 19

incidence.

Question 20

The law of reflection applies to​: a) light; b) sound; c) Both a. and b.​; d) None of the above.

Answer 20

c) Both a. and b.

Question 21

_______ _____ is same size as object, formed behind a mirror, and located at the position where the extended reflected rays converge. ​

Answer 21

Blank 1: Virtual
Blank 2: image​

Virtual image is as far behind the mirror as the object is in front of the mirror.

Question 22

In a _____ ______ the only axis reversed in an image is the front-back axis.​

Answer 22

Blank 1: plane
Blank 2: mirror​

Real world: Right-handed coordinate system​
Mirror Image world: Left-handed coordinate system​

Question 23

______ mirror the virtual image is smaller and closer to the mirror than the object.​

Answer 23

Convex; (curves outward)

Question 24

_______ mirror the virtual image is larger and farther away than the object.​

Answer 24

Concave; (curves inward)

Question 25

Light reflecting from a smooth surface undergoes a change in​: a) frequency; b) speed; c) wavelength; d) None of the above.​
​

Answer 25

d) None of the above.​

Question 26

Bending of light when it passes from one medium to another​?

Answer 26

Refraction;

Caused by change in speed of light.

Question 27

When light travels from one medium to another and changes speed in doing so, we call the process​: a) reflection; b) interference; c) dispersion; d) refraction.

Answer 27

d) refraction.

Question 28

The principle of least time?

Answer 28

Refraction

Question 29

Light travels ______ in glass than in air.

Answer 29

slower; thus it minimizes the time it spends in the glass (refraction).​ Light follows a less inclined path in the glass.

Question 30

Pathways are __________ for both reflection and refraction.​

Answer 30

reversible

Question 31

Refracted light that bends TOWARD the normal is light that has​: a) slowed down; b) sped up; c) nearly been absorbed; d) diffracted.​
​

Answer 31

a) slowed down.

Question 32

Refracted light that bends AWAY from the normal is light that has​: a) slowed down; b) sped up; c) nearly been absorbed; d) diffracted.​
​

Answer 32

b) sped up.

Question 33

Index of refraction​ (n) indicates how much the speed of _____ differs from its speed in a ​______.

Answer 33

Blank 1: light
Blank 2: vacuum.

Indicates the extent of bending of rays.​ The ratio of speed of light in a vacuum to the speed in a material.​

Question 34

A medium with a high index means high _______ effect and greatest slowing of _____.​

Answer 34

Blank 1: bending
Blank 2: light

Index of refraction

Question 35

Objects such as the Sun seen through air are _________ because of atmospheric _________.​

Answer 35

Blank 1: displaced

Blank 2: refraction

Question 36

Light travels ______ in hot air.

Answer 36

faster

Question 37

The action of lenses depends mainly on​: a) reflection; b) refraction; c) Both a. and b.​; c) Neither a. nor b.​
​

Answer 37

b) refraction.

Question 38

A convex lens​ is thicker at the center than edges​

and _________ light​.

Answer 38

converges.

A converging lens can project an image.

Question 39

A concave lens​ is thinner at the center than edges​ and ________ light​.

Answer 39

diverges

Question 40

All are key features of ______:
Principal axis​: line joining the centers of curvature of the two lens surfaces​; Focal point​: point at which all the light rays come together​; Focal length​: distance between the center of the lens and either focal point​.
​

Answer 40

lenses​