Chapter 26: Properties of Light

Question 1

Most of the waves in the electromagnetic spectrum are: a) gamma rays; b) infrared light; c) green light; d) not visible to the human eye; e) microwaves.

Answer 1

d) not visible to the human eye.

Question 2

The fact that light travels at 300,000 km/s is a consequence of: a) electromagnetic wave propagation; b) electromagnetic field induction; c) Maxwell’s laws; d) energy conservation.

Answer 2

d) energy conservation.

Question 3

Which of these electromagnetic waves has the shortest wavelength: a) radio waves; b) infrared waves; c) X-rays; d) ultraviolet waves; e) light waves.

Answer 3

c) X-rays.

Question 4

Which of the following is fundamentally different from the others: a) sound waves; b) X-rays; c) gamma rays; d) light waves; e) radio waves.

Answer 4

a) sound waves.

Question 5

Infrared waves are often called heat waves because they: a) emanate from relatively hot sources; b) consist of frequencies lower than those of visible light; c) induce resonance in molecules and increase internal energy in a substance; d) are absorbed rather than reflected by the skin; e) infrared is hard to pronounce.

Answer 5

c) induce resonance in molecules and increase internal energy in a substance.

Question 6

Visible light radiation travels fastest in: a) air; b) vacuum; c) water; d) glass; e) diamond.

Answer 6

b) vacuum.

Question 7

Color vision and detail are perceived with: a) the rods; b) the cones; c) the macula; d) the cornea; e) the pupilometric.

Answer 7

b) the cones.

Question 8

Which of the following electromagnetic waves have the highest frequency: a) microwaves; b) X-rays; c) infrared; d) visible light; e) gamma rays.

Answer 8

e) gamma rays.

Question 9

Glass is transparent to

Answer 9

all visible light.

Question 10

The atmosphere is transparent to

Answer 10

visible light, some ultraviolet light, and some infrared light.

Question 11

A solar eclipse occurs when the: a) sun passes into Earth’s shadow; b) moon passes into the Earth’s shadow; c) the moon’s shadow touches Earth.

Answer 11

c) the moon’s shadow touches Earth.

Question 12

The cones in the retina of the eye are: a) most densely packed at the center of vision; b) uniformly spread along the visual field; c) concentrated along the periphery of vision.

Answer 12

a) most densely packed at the center of vision.

Question 13

The moon would be at its fullest just before the time of a: a) solar eclipse; b) lunar eclipse; c) both of these; d) none of these.

Answer 13

b) lunar eclipse

Question 14

Compared to ultraviolet waves, the wavelength of infrared waves is: a) shorter. b) longer; c) the same.

Answer 14

b) longer.

Question 15

Materials generally become warmer when light is: a) absorbed by them; b) reflected by them; c) transmitted by them; d) all of these; e) none of these.

Answer 15

a) absorbed by them.

Question 16

The main difference between a radio wave and a sound wave is their different: a) frequencies; b) wavelengths; c) energies; d) amplitudes; e) modes of travel.

Answer 16

e) modes of travel.

Question 17

Which of the following cannot travel in a vacuum: a) a light wave; b) a sound wave; c) a radio wave; d) All can travel in a vacuum; e) None can travel in a vacuum.

Answer 17

b) a sound wave.

Question 18

The Earth’s atmosphere is transparent to most waves in the: a) infrared part of the spectrum; b) visible part of the spectrum; c) ultraviolet part of the spectrum; d) entire electromagnetic spectrum.

Answer 18

b) visible part of the spectrum.

Question 19

The speed of light in the void between molecules in glass is: a) more than its speed in a vacuum; b) the same as its speed in a vacuum; c) less than its speed in a vacuum.

Answer 19

b) the same as its speed in a vacuum.

Question 20

While Earth is experiencing a total solar eclipse, an observer on the side of the moon facing the Earth would see: a) Earth disappear from the sky; b) Earth dim and turn reddish; c) nothing unusual; d) a tiny dark spot move across the face of Earth.

Answer 20

d) a tiny dark spot move across the face of Earth.

Question 21

The main difference between a radio wave and a light wave is its: a) speed; b) wavelength; c) frequency; d) all of these; e) two of these.

Answer 21

e) two of these.

What are the two main differences?

Question 22

When ultraviolet light is incident upon glass, atoms in the glass: a) are forced into vibration; b) resonate; c) pass the light energy along practically undiminished; d) freely absorb and re-emit most of the ultraviolet light.

Answer 22

b) resonate.

Question 23

Electromagnetic waves consist of: a) compressions and rarefactions of electromagnetic pulses; b) oscillating electric and magnetic fields; c) particles of light energy; d) high-frequency gravitational waves.

Answer 23

b) oscillating electric and magnetic fields.

Question 24

If the sun were to disappear right now, we wouldn’t know about it for 8 minutes because it takes 8 minutes: a) for the sun to disappear; b) to operate receiving equipment in the dark; c) for light to travel from the sun to the Earth; d) none of these .

Answer 24

c) for light to travel from the sun to the Earth.

Question 25

Sunburns are produced by

Answer 25

ultraviolet light.

Question 26

Vibrations given by light to their atoms and molecules are turned into random

Answer 26

kinetic energy—into internal energy.

Question 27

A total shadow is called an _______ and ​
a partial shadow is called a ___________. ​

​

Answer 27

1st blank: umbra
2nd blank: penumbra

When we stand in the sunlight, some of the light is stopped while other rays continue in a straight-line path. ​

Question 28

A __________ appears where some of the light is blocked but where other light fills it in. ​

Answer 28

penumbra;

A penumbra also occurs where light from a broad source is only partially blocked.​

Question 29

Speed of light in glass may vary (less), but the _________ transmitted is the same.

Answer 29

frequency

Question 30

The brightest light that the human eye can perceive without damage is some ____ ________ times brighter than the dimmest light that can be perceived.​

Answer 30

500 million

Question 31

_______ _________ means we don’t perceive the actual differences in brightness.

Answer 31

Lateral inhibition

The brightest places in our visual field are prevented from outshining the rest.​