Deck 5: Light and Matter: Reading Messages from the Cosmos

Question 1

We can see each other in the classroom right now because we

A)emit thermal radiation.
B)emit visible light.
C)emit infrared light.
D)reflect visible light.
E)reflect infrared light.

Answer 1

D

Question 2

Without telescopes or other aid,we can see the Moon because it

A)emits visible light.
B)emits thermal radiation.
C)reflects infrared light.
D)reflects visible light.
E)glows through radioactive decay.

Answer 2

D

Question 3

How much electrical charge does an atom with 6 protons,6 neutrons,and 5 electrons have?

A)a total charge of +17
B)a negative charge of -5
C)a positive charge of +7
D)a positive charge of +1
E)none of the above

Answer 3

D

Question 4

From lowest energy to highest energy,which of the following correctly orders the different categories of electromagnetic radiation?

A)infrared,visible light,ultraviolet,X-rays,gamma rays,radio
B)radio,infrared,visible light,ultraviolet,X-rays,gamma rays
C)visible light,infrared,X-rays,ultraviolet,gamma rays,radio
D)gamma rays,X-rays,visible light,ultraviolet,infrared,radio
E)radio,X-rays,visible light,ultraviolet,infrared,gamma rays

Question 5

How are wavelength,frequency,and energy related for photons of light?

A)Longer wavelength means lower frequency and lower energy.
B)Longer wavelength means higher frequency and lower energy.
C)Longer wavelength means higher frequency and higher energy.
D)Longer wavelength means lower frequency and higher energy.
E)There is no simple relationship because different photons travel at different speeds.

Question 6

What is a compound?

A)a group of molecules
B)a molecule containing hydrogen
C)a molecule containing two or more elements
D)an ionized molecule
E)a molecule containing carbon

Question 7

Which of the following cannot be described by a field?

A)gravitational forces
B)electrical forces
C)magnetic forces
D)radiation pressure

Question 8

The frequency of a wave is

A)the number of peaks passing by any point each second.
B)measured in cycles per second.
C)measured in hertz (Hz).
D)equal to the speed of the wave divided by the wavelength of the wave.
E)all of the above

Question 9

Which of the following statements about X-rays and radio waves is not true?

A)Neither X-rays nor radio waves can penetrate the earth's atmosphere.
B)X-rays have shorter wavelengths than radio waves.
C)X-rays and radio waves are both forms of light,or electromagnetic radiation.
D)X-rays have higher frequency than radio waves.
E)X-rays have higher energy than radio waves.

Question 10

The wavelength of a wave is

A)how strong the wave is.
B)the distance between a peak of the wave and the next trough.
C)the distance between two adjacent peaks of the wave.
D)the distance between where the wave is emitted and where it is absorbed.
E)equal to the speed of the wave times the wave's frequency.

Question 11

Everything looks red through a red filter because

A)the filter emits red light and absorbs other colors.
B)the filter absorbs red light and emits other colors.
C)the filter transmits red light and absorbs other colors.
D)the filter reflects red light and transmits other colors.

Question 12

Compared to the volume of its nucleus,the volume of an atom is about

A)the same.
B)a thousand times greater.
C)a million times greater.
D)a billion times greater.
E)a trillion times greater.

Question 13

Which of the following statements about X-rays and radio waves is not true?

A)X-rays have shorter wavelengths than radio waves.
B)X-rays and radio waves are both forms of light,or electromagnetic radiation.
C)X-rays have higher frequency than radio waves.
D)X-rays have higher energy than radio waves.
E)X-rays travel through space faster than radio waves.

Question 14

If you have a 100-watt light bulb,how much energy does it use each minute?

A)6,000 joules
B)6,000 watts
C)600 joules
D)600 watts
E)100 joules

Question 15

Grass appears green because

A)it emits green light and absorbs other colors.
B)it absorbs green light and emits other colors.
C)it transmits green light and emits other colors.
D)it reflects green light and absorbs other colors.

Question 16

When light reflects off an object,what is the relation between the angle of incidence and the angle of reflection?

A)angle of incidence = angle of reflection
B)angle of incidence + angle of reflection = 90°
C)angle of incidence + angle of reflection = 180°
D)angle of incidence - angle of reflection = 90°
E)It depends on the material that the light reflects off.

Question 17

If a material is highly opaque,then it

A)reflects most light.
B)absorbs most light.
C)transmits most light.
D)scatters most light.
E)emits most light.

Question 18

How many atoms fit across the period at the end of this sentence?

A)hundreds
B)thousands
C)millions
D)billions
E)more than you could count in a lifetime

Question 19

From shortest to longest wavelength,which of the following correctly orders the different categories of electromagnetic radiation?

A)infrared,visible light,ultraviolet,X-rays,gamma rays,radio
B)radio,infrared,visible light,ultraviolet,X-rays,gamma rays
C)visible light,infrared,X-rays,ultraviolet,gamma rays,radio
D)gamma rays,X-rays,ultraviolet,visible light,infrared,radio
E)gamma rays,X-rays,visible light,ultraviolet,infrared,radio

Question 20

If a material is transparent,then it

A)reflects light well.
B)absorbs light well.
C)transmits light well.
D)scatters light well.
E)emits light well.

Question 21

Vaporization is the process in which

A)molecules go from the solid phase to the liquid phase.
B)molecules go from the liquid phase to the gas phase.
C)molecules go from the solid phase to the gas phase.
D)electrons are stripped from atoms.
E)electrons are captured by ions.

Question 22

When an atom loses an electron,it becomes

A)vaporized.
B)dissociated.
C)ionized.
D)an isotope.
E)a plasma.

Question 23

An atom of the element iron has an atomic number of 26 and an atomic weight of 56.If it is neutral,how many protons,neutrons,and electrons does it have?

A)26 protons,30 neutrons,26 electrons
B)26 protons,30 neutrons,30 electrons
C)26 protons,56 neutrons,26 electrons
D)13 protons,43 neutrons,13 electrons
E)13 protons,56 neutrons,13 electrons

Question 24

Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms isotopes of each other?

A)Atom 1: nucleus with 6 protons and 8 neutrons,surrounded by 6 electrons Atom 2: nucleus with 7 protons and 8 neutrons,surrounded by 7 electrons
B)Atom 1: nucleus with 8 protons and 8 neutrons,surrounded by 8 electrons Atom 2: nucleus with 8 protons and 8 neutrons,surrounded by 7 electrons
C)Atom 1: nucleus with 92 protons and 143 neutrons,surrounded by 92 electrons Atom 2: nucleus with 92 protons and 146 neutrons,surrounded by 92 electrons
D)Atom 1: nucleus with 1 proton and 0 neutrons,surrounded by 1 electron Atom 2: nucleus with 2 protons and 2 neutrons,surrounded by 2 electrons
E)Atom 1: nucleus with 4 protons and 5 neutrons,surrounded by 4 electrons Atom 2: nucleus with 5 protons and 5 neutrons,surrounded by 4 electrons

Question 25

How can an electron in an atom lose energy to go from a higher energy level to a lower energy level?

A)It loses kinetic energy.
B)It releases a photon equal in energy to its own energy drop.
C)It absorbs a photon equal in energy to its own energy drop.
D)It loses gravitational potential energy.
E)It exchanges gravitational potential energy for kinetic energy.

Question 26

Which of the following statements about electrical charge is true?

A)Two negative charges will attract each other.
B)Two positive charges will attract each other.
C)A positive charge and a negative charge will repel each other.
D)A positive charge and a negative charge will attract each other.

Question 27

Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons.If it is doubly ionized,what is the charge of the gold ion and how many electrons remain in the ion?

A)The gold ion has a charge of +2 and 77 electrons.
B)The gold ion has a charge of +2 and 79 electrons.
C)The gold ion has a charge of -2 and 77 electrons.
D)The gold ion has a charge of +2 and 2 electrons.
E)The gold ion has a charge of +79 and no electrons.

Question 28

The loss of an electron from a neutral helium atom results in

A)neutral hydrogen.
B)ionized hydrogen.
C)ionized helium.
D)neutral deuterium.
E)ionized deuterium.

Question 29

An electron-volt is

A)the charge of one electron.
B)the energy of one electron.
C)the energy jump between the first and second energy levels of hydrogen.
D)an amount of energy much smaller than a joule.
E)an amount of energy much larger than a joule.

Question 30

Which of the following statements about electrons is not true?

A)Electrons orbit the nucleus rather like planets orbiting the Sun.
B)Within an atom,an electron can have only particular energies.
C)Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.
D)An electron has a negative electrical charge.
E)Electrons have very little mass compared to protons or neutrons.

Question 31

Dissociation is the process in which

A)the bonds between atoms in a molecule are broken.
B)a molecule goes from the solid phase to the gas phase.
C)the bonds between electrons around an atomic nucleus are broken.
D)an element changes into another form.
E)an electron is shared between atomic nuclei.

Question 32

When an atom absorbs a photon containing energy,any of the following can happen except which?

A)The atom becomes excited.
B)The atom is ionized.
C)An electron moves from an upper energy level to a lower one.
D)An electron moves from a lower energy level to an upper one.

Question 33

An atom in an excited state contains more of what type of energy than the same atom in the ground state?

A)mass-energy
B)kinetic energy
C)thermal energy
D)gravitational potential energy
E)electric potential energy

Question 34

Oxygen has atomic number 8.How many times must an oxygen atom be ionized to create an O⁺⁵ ion,and how many electrons will the ion have?

A)It must be ionized three times;it now has five electrons.
B)It must be ionized five times;it now has five electrons.
C)It must be ionized five times;it now has three electrons.
D)It doesn't have to be ionized;it just needs to gain five protons.
E)It doesn't have to be ionized;it already has only three electrons.

Question 35

Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons.What is its atomic number and atomic weight?

A)The atomic number is 79,and the atomic weight is 197.
B)The atomic number is 79,and the atomic weight is 118.
C)The atomic number is 118,and the atomic weight is 197.
D)The atomic number is 118,and the atomic weight is 79.

Question 36

At extremely high temperatures (e.g. ,millions of degrees),which of the following best describes the phase of matter?

A)a gas of rapidly moving molecules
B)a plasma consisting of positively charged ions and free electrons
C)a gas consisting of individual,neutral atoms,but no molecules
D)a plasma consisting of rapidly moving,neutral atoms
E)none of the above (At these extremely high temperatures,matter cannot exist. )

Question 37

If you heat a gas so that collisions are continually bumping electrons to higher energy levels,when the electrons fall back to lower energy levels the gas produces

A)thermal radiation.
B)an absorption line spectrum.
C)an emission line spectrum.
D)X-rays.
E)radio waves.

Question 38

When an electron in an atom goes from a higher energy state to a lower energy state,the atom

A)emits a photon of a specific frequency.
B)absorbs a photon of a specific frequency.
C)absorbs several photons of a specific frequency.
D)can emit a photon of any frequency.
E)can absorb a photon of any frequency.

Question 39

The study of energy levels in atoms is called

A)special relativity.
B)general relativity.
C)quantum mechanics.
D)classical mechanics.
E)particle physics.

Question 40

Suppose you built a scale-model atom in which the nucleus was the size of a tennis ball.About how far would the cloud of electrons extend?

A)several centimeters
B)a few meters
C)a few tens of meters
D)several kilometers
E)to the Sun

Question 41

How does the spectrum of a molecule differ from the spectrum of an atom?

A)A molecule does not have spectral lines due to electrons changing energy levels.
B)A molecule has additional spectral lines due to changes in its rotational and vibrational energies.
C)Molecules only have spectral lines at ultraviolet wavelengths.
D)Most atoms only have spectral lines at infrared wavelengths.
E)An atom has a wider range of spectral lines than molecules.

Question 42

Thermal radiation is defined as

A)radiation produced by a hot object.
B)radiation in the infrared part of the spectrum.
C)radiation that depends only on the emitting object's temperature.
D)radiation in the form of emission lines from an object.
E)radiation that is felt as heat.

Question 43

If we observe one edge of a star to be redshifted and the opposite edge to be blueshifted,what can we conclude about the star?

A)The star is actually two bodies,one moving toward us,the other away from us.
B)The star is in the process of falling apart.
C)The star is in the process of formation.
D)The star is rotating.
E)The star's surface is very different from one side to the other.

Question 44

Suppose you see two stars: a blue star and a red star.Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved.(Hint: Think about the laws of thermal radiation. )

A)The red star is more massive than the blue star.
B)The blue star is more massive than the red star.
C)The blue star is farther away than the red star.
D)The blue star has a hotter surface temperature than the red star.
E)The red star has a hotter surface temperature than the blue star.

Question 45

Which of the following statements about thermal radiation is always true?

A)A hot object emits photons with a longer wavelength than a cool object.
B)A hot object emits photons with a higher average energy than a cool object.
C)A hot object emits more radio waves than a cool object.
D)A hot object emits more X-rays than a cool object.

Question 46

If one object has a large redshift and another object has a small redshift,what can we conclude about these two objects?

A)The one with the large redshift is moving toward us faster than the one with the small redshift.
B)The one with the large redshift is moving away from us,and the one with the small redshift is moving toward us.
C)The one with the large redshift is moving away from us faster than the one with the small redshift.
D)The one with the large redshift is hotter and therefore is putting out more radiation.
E)The one with the large redshift is redder than the other one.

Question 47

The spectra of most galaxies show redshifts.This means that their spectral lines

A)always are in the red part of the visible spectrum.
B)have wavelengths that are longer than normal.
C)have wavelengths that are shorter than normal.
D)have a higher intensity in the red part of the spectrum.
E)have normal wavelengths,but absorption of light makes them appear red.

Question 48

From laboratory measurements,we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm).The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm.What can we conclude?

A)The star is moving toward us.
B)The star is moving away from us.
C)The star is getting hotter.
D)The star is getting colder.
E)The "star" actually is a planet.

Question 49

You observe the same spectral line in two stars that are identical in every way except that one rotates faster than the other.How does the spectral line differ between the two?

A)There is no difference.
B)The line in the faster rotating star is blueshifted.
C)The line in the faster rotating star is redshifted.
D)The line in the faster rotating star is broader.
E)The line in the faster rotating star is narrower.

Question 50

A perfectly opaque object that absorbs all radiation and reemits the absorbed energy as thermal radiation is

A)a hot,dense cloud of gas.
B)a cold,dense cloud of gas.
C)an infrared radiation emitter.
D)a thermal emitter.
E)transparent.

Question 51

Spectra from neutral atoms compared with spectra from ionized atoms of the same element

A)are the same.
B)are slightly redshifted.
C)are slightly blueshifted.
D)have different sets of spectral lines.
E)have the same sets of spectral lines but different widths for those lines.

Question 52

Energy and power are different words for the same thing.

Question 53

We can learn a lot about the properties of a star by studying its spectrum.All of the following statements are true except one.Which one?

A)The peak of the star's thermal emission tells us its temperature: Hotter stars peak at shorter (bluer)wavelengths.
B)The total amount of light in the spectrum tells us the star's radius.
C)We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals.
D)We can look at Doppler shifts of spectral lines to determine the star's speed toward or away from us.

Question 54

When white light passes through a cool cloud of gas,we see

A)visible light.
B)infrared light.
C)thermal radiation.
D)an absorption line spectrum.
E)an emission line spectrum.

Question 55

A gas heated to millions of degrees would emit

A)mostly radio waves.
B)mostly X-rays.
C)mostly ultraviolet light.
D)an equal amount of all wavelengths of light.
E)no light,because it is too hot.

Question 56

If two objects are the same size but one object is 3 times hotter than the other object,the hotter object emits

A)3 times more energy.
B)9 times more energy.
C)12 times more energy.
D)81 times more energy.
E)none of the above

Question 57

Which of the following statements about thermal radiation is always true?

A)A hot object emits more X-rays than a cool object.
B)A hot object emits more radio waves than a cool object.
C)A hot object emits more total radiation than a cool object.
D)A hot object emits more total radiation per unit surface area than a cool object.
E)A hot object emits less total radiation than a cool object.

Question 58

Which of the following objects is not a close approximation of a thermal emitter?

A)hot,thin gas
B)a star
C)a filament in a light bulb
D)you
E)a planet

Question 59

You observe a distant galaxy.You find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared.What do you conclude?

A)The galaxy is moving away from you.
B)The galaxy is moving toward you.
C)The galaxy has very weak gravity.
D)The galaxy is made purely of hydrogen.
E)The composition of the galaxy is changing.

Question 60

From laboratory measurements,we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm).The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm.What can we conclude?

A)The star is moving toward us.
B)The star is moving away from us.
C)The star is getting hotter.
D)The star is getting colder.
E)The "star" actually is a planet.

Question 61

Suppose you have a chunk of water ice.Describe what happens to it,in terms of phases,as you raise the temperature to millions of degrees.

Question 62

There are more atoms in a glass of water than stars in the observable universe.

Question 63

The energy levels for electrons vary from one element to another.

Question 64

Any object moving relative to Earth will have a Doppler shift.

Question 65

What does atomic number refers to?

Question 66

Emission lines from different ionization states of the same element appear in the same place in the spectrum.

Question 67

Define atomic weight (or atomic mass).

Question 68

You are currently emitting electromagnetic waves.

Question 69

Electrons orbit an atomic nucleus like planets orbit the Sun.

Question 70

X-rays,because they have more energy,travel through space faster than visible light.

Question 71

The atomic nuclei of the same element always have the same number of neutrons.

Question 72

Atomic nuclei consist of protons and electrons.

Question 73

Lines of a particular element appear at the same wavelength in both emission and absorption line spectra.

Question 74

X-rays always have more energy than radio waves.

Question 75

The atomic nuclei of the same element always have the same number of protons.

Question 76

The shorter the wavelength of light,the higher its frequency.

Question 77

Process of Science: I am doing science when I already know the answer to my scientific question and I am searching for evidence in the natural world strictly to support what I know.

Question 78

The greater the wavelength of light,the greater its energy.

Question 79

The energy levels of an element and its ion are the same.

Question 80

Grass is green because it absorbs green light,reflecting all other colors.