Astro Sfa 105 Ch5 Light

Front 1

What is the term for the dispersion of light into a rainbow when it passes through a prism

Back 1

Spectrum

Front 2

What is the term for the light from the Sun as it appears when we pass it through a prism or similar device?

Back 2

Spectrum

Front 3

T or F
Is the Sun's spectrum a pure rainbow?

Back 3

No, is shows hundreds of dark lines

Front 4

Who conducted experiments that were the first to provide insights into the nature of light?

Back 4

Isaac Newton

Front 5

T or F
Newton proved that the colors came from the light by placing a second prism in front of the light of just one color.

Back 5

True

Front 6

T or F
When only blue light enters a second prism only blue light will emerge.

Back 6

True

Front 7

What is white light?

Back 7

A mix of all the colors in the rainbow

Front 8

T or F
Is there light beyond the rainbow that we cannot see with the naked eye?

Back 8

True

Front 9

What is the term for the complete spectrum of light?

Back 9

Electromagnetic spectrum

Front 10

What is the term for the light itself?

Back 10

Electromagnetic radiation

Front 11

What is the term for something that can transmit energy without carrying material along with it?

Back 11

A wave

Front 12

What is the term for the distance between adjacent peaks in a wave?

Back 12

The Wavelength

Front 13

What is the term for the number of times that nay piece of a wave moves up and down each second?

Back 13

Frequency

Front 14

What is the term that is used to represent "per second"?

Back 14

hertz

Front 15

T or F
Light can affect both electrically charged particles and magnets.

Back 15

True

Front 16

T or F
Not light waves travel through empty space at the same speed.

Back 16

False,
All light travels through empty space at the same speed.

Front 17

What is the approx. speed of light?

Back 17

300,000 kilometers per second

Front 18

Re; light,
The longer the wavelength, the ________ the frequency?

Back 18

The longer the wavelength, the lower the frequency.

Front 19

Re: light,
The shorter the wavelength, the ______________ the frequency.

Back 19

The shorter the wavelength, the higher the frequency.

Front 20

T or F
Light can behave both as a wave and as a particle.

Back 20

True

Front 21

What is the term for the "pieces" of light?

Back 21

photons

Front 22

At speed do photons travel?

Back 22

The speed of light, 300,000 kilometers per second

Front 23

What is the relationship between photon and energy?

Back 23

The higher the frequency of the photon, the more energy it carries.

Front 24

What are the wavelength ranges of visible light?

Back 24

@400nm to 700nm

Front 25

What is the wavelength of blue light?

Back 25

@ 400 nm

Front 26

What is the wavelength of red light?

Back 26

@700 nm

Front 27

What is a nm?

Back 27

A nanometer

Front 28

What does a nm equal?

Back 28

one billionth of a meter or
1/1,000,000,000 of a meter

Front 29

What is the term given to light with wavelengths somewhat longer than red light?

Back 29

infrared, because it lies beyond the red end of the rainbow

Front 30

What waves have the longest wavelength of light?

Back 30

Radio waves

Front 31

T or F
Radio waves are sound waves.

Back 31

False,
Radio waves are a form of light waves.

Front 32

What is the term for the region near the border between infrared and radio waves, where wavelengths range from micrometers to millimeters?

Back 32

Microwaves

Front 33

What is the term for light with wavelengths somewhat shorter than blue light?

Back 33

Ultraviolet, because it lies beyond the blue (or violet) end of the rainbow

Front 34

What is the term for the light with even shorter wavelengths than ultraviolet?

Back 34

X rays

Front 35

What is the term given to the shortest-wavelength light?

Back 35

Gamma rays

Front 36

Compared to x rays, how long are radio waves

Back 36

Radio waves are a billion times as long as X rays

Front 37

T or F
Radio waves carry so little energy that they have no noticeable effect on our bodies.

Back 37

True

Front 38

Why do we associate infrared light with heat?

Back 38

Molecules moving around in a warm object emit infrared light?

Front 39

T or F
E ray photons have enough energy to penetrate through skin and muscle but can be blocked by bones or teeth

Back 39

True

Front 40

Name the four elements that the ancient Greeks imagined that all material was made from?

Back 40

1. Fire
2. water
3. Earth
4. air

Front 41

Name the tiniest particle of each chemical element?

Back 41

Atom

Front 42

What particles lie in the atom's nucleus?

Back 42

1. protons
2. neutrons

Front 43

Where is most of the mass of an atom located?

Back 43

The nucleus

Front 44

What do the properties of an atom depend mainly upon?

Back 44

The electrical charge in the atom's nucleus

Front 45

What is the basic unit of positive charge?

Back 45

The electrical charge of a proton or +1

Front 46

What charge is the electrical charge that is exactly the opposite of that of a proton?

Back 46

Electron or -1

Front 47

What particle is neutrally charged?

Back 47

Neutron

Front 48

T or F
Oppositely charged particles repel each other.

Back 48

False,
Oppositely charged particles attract each other.

Front 49

What holds an atom together?

Back 49

The attraction between the positively charged protons in the nucleus and the negatively charged electrons that surrond the nucleus.

Front 50

What particles in an atom form a kind of "smeared out" cloud that surround the nucleus and give the atom its apparent size?

Back 50

Electrons

Front 51

T or F
Atoms of diferent chemical elements have different numbers of protons.

Back 51

True

Front 52

What is the term given to the unique number of each element's protons in its nucleus?

Back 52

Atomic number

Front 53

What is the term for the combined number of protons and neutrons in an atom?

Back 53

Atomic mass number

Front 54

T or F
Every atom of a given element contains exactly the same number of protons, but the number of neutrons can vary.

Back 54

True

Front 55

What is the term given to the different versions of an element with different numbers of neutrons?

Back 55

Isotopes of the element

Front 56

How are isotopes named?

Back 56

By listing their element name and atomic mass number

Front 57

How do you read the isotope

12
C ?

Back 57

Carbon-12

Front 58

What is the term for the different material substances that are formed when atoms from different elements are combined?

Back 58

Molecules

Front 59

Name the 4 general ways energy carried by light can interact with matter?

Back 59

1. Emission
2. Absorption
3. Transmission
4. Reflection/scattering

Front 60

What is the term used to describe something passing through?

Back 60

Transmission

Front 61

What is the term used to describe light bouncing off matter that is all in the same general direction?

Back 61

Reflection

Front 62

What is the term used to describe light bouncing off matter that is in random directions?

Back 62

Scattering

Front 63

What is the term used to describe materials that transmit light?

Back 63

Transparent

Front 64

What is the term used to describe materials that absorb light?

Back 64

Opaque

Front 65

T or F
Red glass transmits red light but absorbs others colors.

Back 65

True

Front 66

T or F
A green lawn reflects green light but absorbs all other colors.

Back 66

True

Front 67

List the 3 basic types of spectra:

Back 67

1. continuous spectrum
2. emission line spectrum
3. absorption line spectrum

Front 68

What is the term for the broad range of wavelengths without interruption?

Back 68

Continuous spectrum

Front 69

What is the term used to describe the waves that are produced when a material emits light only at specific wavelengths that depend on its composition and temperature?

Back 69

Emission lines

Front 70

What is the term for the spectra that is produced when a material emits light only at specific wavelengths that depend on its composition and temperature?

Back 70

Emission line spectrum

Front 71

What is the term for the spectra that a material absorbs light?

Back 71

Absorption line spectrum

Front 72

What is the term for the amount of the light at each wavelength in the spectrum?

Back 72

Intensity

Front 73

What is the term for the particular energies of electrons in atoms?

Back 73

Energy levels of an atom

Front 74

What does eV represent?

Back 74

electron volts

Front 75

What is the eV at level 1 or the ground state?

Back 75

0 eV.

Front 76

What is the term given to each of the higher energy levels above the ground state?

Back 76

Excited states

Front 77

How do energy level transitions occur?

Back 77

Only when an electron gains or loses the specific amount of energy separating 2 levels.

Front 78

T or F
It takes more energy to raise the electron from level 1 to level 2 than from level 2 to level 3.

Back 78

True

Front 79

What is the term for electrically charged atoms?

Back 79

Ions

Front 80

What happens if the electron gains enough energy to reach the ionization level?

Back 80

The electron escapes the atom, leaving the atom with a positive charge.

Front 81

T or F
Each type of atom, ion, or molecule possesses a unique set of energy levels and that is what cause emission and absorption lines to appear at specific wavelengths in spectra.

Back 81

True

Front 82

`T or F
Electrons can stay at higher energy levels for a long time.

Back 82

False,
Electrons cannot stay in higher energy levels for long, they always fall back down to level 1 in fractions of a second

Front 83

What happens to the energy from the electron that loses when it falls to the lower energy level?

Back 83

A photon of light is emitted.

Front 84

T or F
The photon emitted from an electron falling to a lower energy level must have the same amount of energy the electron loses.

Back 84

True

Front 85

T or F
No real object emits a perfect thermal radiation spectrum.

Back 85

True

Front 86

What is Law 1 of Thermal radiation also known as?

Back 86

Stefan-Boltzmann law

Front 87

What is the Law 1 of thermal radiation?

Back 87

Each square meter of a hotter object's surface emits more light at all wavelengths

Front 88

What is Law 2 of Thermal radiation also known as?

Back 88

Wien's law (pronounced veen)

Front 89

What is the Law 2 of thermal radiation?

Back 89

Hotter objects emit photons with a higher average energy,
which means a shorter average wavelength

Front 90

Why is "white hot" hotter than "red hot"?

Back 90

When a material gets hotter, the average wavelength of the emitted photons move towards the shorter wavelength end of the spectra, the mix appearing to your eyes as white

Front 91

What does thermal radiation spectra depend on?

Back 91

Temperature

Front 92

What causes changes in an object's light spectra that causes the apparent motion of a distant object?

Back 92

The Doppler effect

Front 93

What happens to the light waves from an object moving towards us?

Back 93

The light waves bunch up between us and the object, so that its entire spectrum is shifted to shorter wavelengths

Front 94

What is the term for the Doppler shift of an object coming towards us?

Back 94

Blue shift

Front 95

What happens to the light waves from an object moving away from us?

Back 95

The light is shifted to longer wavelengths

Front 96

What is the term for the Doppler shift of an object moving away from us?

Back 96

Redshift

Front 97

What is the term for wavelengths of a material that is stationary?

Back 97

rest wavelengths

Front 98

The larger the Doppler shift, the ________ the object is moving.

Back 98

The larger the shift, the faster the object is moving.

Front 99

T or F
Doppler shifts give us information about the speed of an object that is moving across our line of sight.

Back 99

False,
Doppler shifts do not give us any information about how fast an object is moving across our line of sight.

Front 100

What are the instruments that are essentially giant eyes that can collect far more light than our naked eyes?

Back 100

Telescopes

Front 101

List the 2 key properties of a telescope?

Back 101

1. light collecting area
2. angular resolution

Front 102

What is the term for how much total light the telescope can collect at one time?

Back 102

Light-collecting area

Front 103

What shape are telescopes generally?

Back 103

Round

Front 104

How is a telescope's size usually characterized?

Back 104

By the diameter of its light-collecting area.

Front 105

What is the light collecting area of a 10-meter telescope?

Back 105

10 meters in diameter

Front 106

What is the light collecting area proportional to?

Back 106

The square of a telescope's diameter

Front 107

T or F
A relatively small increase in a telescope's diameter can mean a big increase in light collecting area.

Back 107

True

Front 108

What is the term that tells us the smallest angle over which we can tell that 2 dots - or 2 stars- are distinct?

Back 108

Angular resolution

Front 109

T or F
Most larger telescopes should have better angular resolution.

Back 109

True

Front 110

T or F
The smaller the angular resolution, the better the resolution?

Back 110

True

Front 111

What hinders telescopes that are on ground vs in space?

Back 111

The Earth's atmosphere

Front 112

Name the 2 basic designs of telescopes:

Back 112

1. Refracting
2. Reflecting

Front 113

What type of telescope operates much like an eye, using transparent glass lenses to focus the light from distant objects?

Back 113

A Refracting Telescope

Front 114

What type of telescope uses a precisely curved primary mirror to gather light, the mirror reflects the gathered light to a secondary mirror that lies in front to it, which then reflect the light to a focus at a place where the eye or instruments can see it

Back 114

A Reflecting Telescope

Front 115

T or F
Nearly all telescopes used in current astronomical research are refracters.

Back 115

False,
Nearly all telescopes used in current astronomical research are reflectors.

Front 116

Cite one solution to building a telescope with one large primary mirror?

Back 116

Using many smaller mirrors that operate as one, as in the Keck telescopes.

Front 117

What kind of light to planets primarily emit?

Back 117

Infrared, because they are relatively cool.

Front 118

What is the basic idea behind all telescopes?

Back 118

To collect as much light as possible, with as much resolution as possible.

Front 119

Name the largest single telescope in the world?

Back 119

The Arecibo radio dish, that stretches 305 meters (1,000 feet) across a natural valley in Puerto Rico

Front 120

T or F
There are x ray telescopes that are designed to deflect x rays in much the same way as deflecting bullets.

Back 120

True

Front 121

Name the 2 telescopes that operate from space?

Back 121

1. Hubble
2. Chandra X-ray Observatory

Front 122

What is the term for the scattering of light caused by the Earth's atmosphere?

Back 122

Light pollution

Front 123

T or F
Light is distorted on Earth by the turbulence of air.

Back 123

True

Front 124

What is the term used to describe the ever-changing movement of air?

Back 124

Turbulence

Front 125

T or F
Our atmosphere helps most forms of light to reach the ground.

Back 125

False,
Our atmosphere prevents most forms of light from reaching the ground at all.

Front 126

What is the most important reason for putting telescopes in space?

Back 126

To observe light that does not penetrate Earth's atmosphere

Front 127

What type of telescope would be completely useless on the ground?

Back 127

X-ray telescope

Front 128

What are adaptive optics?

Back 128

By changing the shape of the mirrors based on the atmospheric conditions, compensation occurs.

Front 129

What is the term for the technique used since the 1950s that allows 2 or more individual telescopes to achieve the angular resolution of a much larger telescope.

Back 129

Interferometry

Front 130

Name a group of telescopes that are arranged to conduct interferometry in the US?

Back 130

LVA or the Very Large Arry in New Mexico links 27 individual radio dishes laid out in the shape of a Y

Front 131

When is interferometry difficult?

Back 131

For shorter wavelength light, (higher frequency light)

Front 132

What is different about the way telescopes are built today?

Back 132

They are built in pairs so that they can be used for infrared and visible-light interferometry.