Deck 20: Light, Color and Atmospheric Optics

Question 1

Another term for reflected light is diffuse light.

Answer 1

False

Question 2

As sunlight enters the atmosphere, the shorter visible wavelengths of violet, blue, and green are scattered more by atmospheric gases than are the longer wavelengths of yellow, orange, and especially red, which is why the sky appears blue.

Answer 2

True

Question 3

Sun pillars are caused by refraction of sunlight off ice crystals.

Answer 3

False

Question 4

Seeing colors requires more than just light reaching our eyes.

Question 5

The duration of twilight decreases with increasing latitude, especially in summer.

Question 6

The Sun radiates almost half of its energy as visible light.

Question 7

Haze can scatter light from the rising or setting Sun in a way that produces bright light beams, called anticrepuscular rays, radiating across the sky.

Question 8

A superior mirage occurs when the air near the ground is much warmer than the air above, and objects not only appear to be lower than they really are, but also inverted.

Question 9

The breaking up of white light by "selective" refraction is called dispersion of light.

Question 10

Volcanic eruptions rich in sulfur produce yellow sunsets.

Question 11

When the atmosphere becomes loaded with particles, only the longest red wavelengths are able to penetrate the atmosphere, so we see a red Sun.

Question 12

To see a rainbow, people must face the falling rain with the Sun at their backs.

Question 13

A star much hotter than our Sun radiates more energy at shorter wavelengths and thus appears redder.

Question 14

Occasionally, when the size of the suspended particles is similar to the primary wavelengths of visible light, the Sun can appear blue, even at noon.

Question 15

If people see a rainbow in the morning, they are facing west toward the rain shower, and it is likely that the clouds and showers will move away from them.

Question 16

The presence of a halo indicates that cirriform clouds are present.

Question 17

A whitish halo around the Sun, or a bright sheen visible in a nearby layer of thin clouds, is often the result of Mie scattering.

Question 18

Light that passes through a substance is said to be refracted.

Question 19

Without the atmosphere, there would be no refraction or scattering, and the Sun would rise later and set earlier than it now does.

Question 20

A corona is due to diffraction of light.

Question 21

Plants appear green to us because they ____.

A)absorb green wavelengths
B)reflect blue wavelengths
C)reflect green wavelengths
D)absorb all visible wavelengths
E)reflect all visible wavelengths

Question 22

When the atmosphere becomes loaded with particles, only the ____ red wavelengths are able to penetrate the atmosphere, and we see a ____ Sun.

A)longest; red
B)shortest; red
C)longest; blue
D)shortest; white
E)longest; yellow

Question 23

The blue color of the sky is a result of ____.

A)selective scattering of visible light by air molecules
B)the filtering effect of water vapor in Earth's atmosphere
C)reflection of sunlight off Earth's oceans
D)transmission of visible light through the ozone layer in Earth's stratosphere
E)absorption of short wavelengths by air molecules

Question 24

What color would the sky be if air molecules selectively scattered only the longest wavelengths of visible light?

A)White
B)Blue
C)Red
D)Black
E)Violet

Question 25

When we look at a cloud, it appears white because countless cloud droplets ____.

A)absorb all wavelengths of visible sunlight
B)reflect all wavelengths of visible sunlight into space
C)scatter all wavelengths of visible sunlight away from Earth
D)scatter all wavelengths of visible sunlight toward Earth
E)scatter all wavelengths of visible sunlight in all directions

Question 26

A star that is cooler than our Sun appears ____.

A)more violet
B)redder
C)brighter
D)whiter
E)bluer

Question 27

When electromagnetic waves from the Sun reach the human eye, they stimulate antenna-like nerve endings in the ____.

A)iris
B)retina
C)pupil
D)cornea
E)sclera

Question 28

Haze can scatter light from the rising or setting Sun in a way that produces bright light beams, called ____, radiating across the sky.

A)anticrepuscular rays
B)crepuscular rays
C)blue haze
D)sun dogs
E)glories

Question 29

If Earth did not have an atmosphere, the sky would appear ____ during the day.

A)white
B)black
C)red
D)blue
E)violet

Question 30

A star much hotter than our Sun radiates more energy at ____.

A)shorter wavelengths and appears redder
B)shorter wavelengths and appears bluer
C)longer wavelengths and appears redder
D)longer wavelengths and appears bluer
E)about the same wavelengths and appears whiter

Question 31

If the setting Sun appears red, you may conclude that ____.

A)the Sun's surface temperature has cooled somewhat at the end of the day
B)the longest wavelengths of visible light are striking your eyes
C)the next day's weather will be stormy
D)you will not be able to see the Moon that night
E)the shortest wavelengths of visible light are striking your eyes

Question 32

White light is perceived when ____ strike(s)the cones of the eye with nearly equal intensity.

A)a single long wavelength
B)a single short wavelength
C)all visible wavelengths
D)all short wavelengths
E)all long wavelengths

Question 33

The blue color of distant mountains is due primarily to ____.

A)diffraction of light
B)scattering of light
C)refraction of light
D)emission of light
E)absorption of light

Question 34

The sky will begin to turn milky white ____.

A)when the concentration of ozone begins to reach dangerous levels
B)when small particles such as dust and salt become suspended in the air
C)when the relative humidity decreases below about 10 percent
D)on an oppressively hot day of the year
E)when an inferior mirage occurs

Question 35

Red sunsets, blue moons, and milky-white skies are mainly the result of ____.

A)refraction
B)dispersion
C)reflection
D)scattering
E)diffraction

Question 36

Which type of particle causes a whitish haze, and a glare in clouds near the Sun?

A)Aerosols
B)Cloud droplets
C)Air molecules
D)Water molecules
E)Nitrous oxide

Question 37

Imagine that a piece of paper is illuminated with white light and appears red. You see red light because the paper ____.

A)absorbs red and reflects other visible wavelengths
B)emits red light
C)reflects red and absorbs other visible wavelengths
D)disperses white light
E)transmits red light

Question 38

Some people will remark that the "Sun appears to be drawing up water" when they are actually observing ____.

A)brocken bow
B)anticrepuscular rays
C)crepuscular rays
D)glories
E)halos

Question 39

The sky is blue because air molecules selectively ____ blue light.

A)scatter
B)absorb
C)diffract
D)disperse
E)emit

Question 40

Another name for diffuse light is ____.

A)scattered light
B)refracted light
C)dispersion of light
D)transmitted light
E)diffracted light

Question 41

____ lasts from sunset until the Sun is 6 degrees below the horizon.

A)Astronomical twilight
B)Civil twilight
C)White night
D)Nightlong twilight
E)Summer twilight

Question 42

When stars appear to twinkle or flicker, it is a condition known as ____.

A)fluctuation
B)iridescence
C)glorification
D)shimmering
E)scintillation

Question 43

When the Sun is 4 degrees above the horizon, sunlight must pass through an atmosphere more than ____ times thicker than when the Sun is directly overhead.

A)2
B)5
C)8
D)12
E)20

Question 44

The green flash is largely an example of the ____ of light by Earth's atmosphere.

A)refraction
B)reflection
C)absorption
D)diffraction
E)transmission

Question 45

Volcanic eruptions rich in ____ can produce red sunsets.

A)water vapor
B)sulfur
C)methane
D)carbon monoxide
E)nitrogen

Question 46

A mirage is caused by ____.

A)scattering of light by air molecules
B)the bending of light by air of different densities
C)a thin layer of moist air near the ground
D)reflection of light from a hot surface
E)refraction of light through ice crystals

Question 47

Twilight is the name given to the time ____, when the sky remains illuminated and allows outdoor activities without artificial lighting.

A)after sunset and immediately before sunrise
B)after sunset and immediately after sunrise
C)before sunset and immediately before sunrise
D)before sunset and immediately after sunrise
E)around sunset

Question 48

For blue Suns to appear, the size of the suspended particles must be ____.

A)shorter than infrared wavelengths
B)similar to ultraviolet wavelengths
C)shorter than the primary wavelengths of visible light
D)similar to the primary wavelengths of visible light
E)similar to the primary wavelengths of visible light

Question 49

Because of atmospheric refraction, a star seen near Earth's horizon is actually ____.

A)slightly higher than it appears
B)slightly lower than it appears
C)slightly brighter than it appears
D)much further away than it appears
E)much dimmer than it appears

Question 50

A reflection of sunlight off ice crystals is called a____.

A)rainbow
B)halo
C)sun pillar
D)sundog
E)glory

Question 51

The phenomenon that can sometimes be seen near the upper rim of a setting or rising Sun is called ____.

A)sun pillar
B)the glory
C)a corona
D)the green flash
E)the Fata Morgana

Question 52

The length of twilight depends on ______.

A)just the seasons
B)just the latitude
C)just the longitude
D)season and latitude
E)season and longitude

Question 53

Halos are caused by ____.

A)refraction of light passing through raindrops
B)scattering of light by ice crystals
C)refraction of light passing through ice crystals
D)diffraction of light by cloud droplets
E)reflection of light by ice crystals

Question 54

Which event would you most likely observe over snow-covered ground in the winter?

A)Superior mirage
B)Sun pillars
C)Crepuscular rays
D)Shimmering
E)Inferior mirage

Question 55

An atmospheric phenomenon that causes objects to appear inverted is called ____.

A)a superior mirage
B)an inferior mirage
C)scintillation
D)dispersion
E)a green flash

Question 56

Which events are caused by the refraction of light through ice crystals?

A)Rainbows and halos
B)Halos and the green flash
C)Halos and sundogs
D)Sundogs and sun pillars
E)Mirages and sundogs

Question 57

Light that travels from a less-dense to a more-dense medium ____ speed and bends ____ the normal.

A)gains; toward
B)loses; toward
C)gains; away
D)loses; away
E)gains; either toward or away

Question 58

At high latitudes during the summer, morning and evening twilight may converge, producing a(n)____, or a nightlong twilight.

A)constructive interference
B)false twilight
C)iridescence
D)white night
E)glory

Question 59

The term parhelia, meaning "with the Sun, " refers to what phenomenon?

A)Halo
B)Sundog
C)Rainbow
D)Glory
E)Corona

Question 60

A wet-looking road surface on a clear, hot, dry day is an example of ____.

A)a superior mirage
B)scintillation
C)diffraction
D)condensation
E)shimmering

Question 61

Which processes must occur in a raindrop to produce a rainbow?

A)Refraction, reflection, and dispersion of sunlight
B)Refraction, reflection, and scattering of sunlight
C)Reflection, scattering, and dispersion of sunlight
D)Transmission, reflection, and dispersion of sunlight
E)Refraction, transmission, and scattering of sunlight

Question 62

Cloud iridescence is most often seen within 20 degrees of the Sun, and it is often associated with clouds such as ____.

A)cirrocumulus and altocumulus
B)cirrocumulus and cumulonimbus
C)altocumulus and stratocumulus
D)nimbostratus and cirrus
E)cirrostratus and cumulonimbus

Question 63

Volcanic eruptions rich in ____________________ can produce red sunsets.

Question 64

When the bright light beams appear to converge toward the part of the horizon opposite from the Sun, the beams of light are called ____________________ rays.

Question 65

____________________ scattering is most noticeable when particles of dust, salt, or smoke are about the same size as the wavelengths of visible light (or between about 0.1 and 1 µm).

Question 66

A star that is cooler than our Sun radiates most of its energy at slightly longer wavelengths; therefore, it appears ____________________.

Question 67

Haze can scatter light from the rising or setting Sun in a way that produces bright light beams, or ____________________ rays, radiating across the sky.

Question 68

When a star appears to twinkle or flicker, it is a condition called ____________________.

Question 69

This forms when sunlight that falls on nearly spherical dewdrops is focused and reflected back toward the Sun along nearly the same path it took originally.

A)Halo
B)Inferior mirage
C)Corona
D)Heiligenschein
E)Sun pillar

Question 70

Selective scattering is also known as ____________________.

Question 71

Fata Morgana are most commonly seen ____.

A)where warm air rests above a cold surface
B)where cold air rests above a hot surface
C)when it is raining above a hot surface
D)when it is raining above a cold surface
E)at noon in middle latitudes

Question 72

If people possessed rod-type receptors only, then only ____________________ vision would be possible.

Question 73

Which statement is true about rainbows?

A)The rainbow will be seen in the west when the Sun is setting.
B)Rainbows form when rays from the Sun are scattered.
C)The brightest rainbows are seen around noon.
D)To see a rainbow at sunrise, you should look toward the west.
E)The rainbow will be seen in the east during sunrise.

Question 74

Sunlight reflecting off ice crystals produces which of the following?

A)Crepuscular rays
B)Halos
C)Sun pillars
D)Sun dogs
E)Glories

Question 75

We perceive light because radiant energy from the Sun travels outward in the form of ____________________ waves.

Question 76

Secondary rainbows occur when ____.

A)two internal reflections of light occur in raindrops
B)light refracts through ice crystals
C)a single internal reflection of light occurs in raindrops
D)light refracts through a cloud of large raindrops
E)the Sun disappears behind a cloud and then reappears

Question 77

Look for sun pillars when the Sun is ____ on the horizon and ____ clouds are present.

A)low; cumulus
B)high; stratus
C)low; stratus
D)high; cirriform
E)low; cirriform

Question 78

A ____ can occur during a full moon, usually when rain is falling in one area of the sky and the Moon is visible in another.

A)Sundog
B)Moonbow
C)rainbow
D)sun pillar
E)corona

Question 79

At sunset in the middle latitudes, look for a rainbow toward the ____.

A)northwest
B)southwest
C)east
D)west
E)south

Question 80

____________________ is the name given to the time after sunset (and immediately before sunrise)when the sky remains illuminated.