Light, The Sun, and Stars Test #1 (ASTR121)

Which law do astronomers use to determine the masses of the stars in a spectroscopic binary system? A. Kepler's 3rd Law B. Wien's Law C. Stefan-Boltzmann Law D. Hubble's Law

A. Kepler's 3rd Law

Astronomers have concluded that the Sun's activity varies in an 11-year cycle. Which of the following statements about this cycle is TRUE: A. The number of sunspots gets larger and smaller over the course of 11 years B. The Sun's activity cycle is directly connected to the number of earthquakes at the continental plate boundaries on Earth C. When sunspots are at a minimum, we get the largest number of flares and prominences D. Every 11 years sunspots completely cover the Sun, making its surface much darker E. The Sun's activity cycle shows absolutely no connection to its magnetic field

A. The number of sunspots gets larger and smaller over the course of 11 years

Which of the following statements about the Sun's photosphere is NOT TRUE? A. The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward) B. Through a telescope, the photosphere looks mottled or granulated C. The photosphere is much less dense than our Earth's atmosphere D. The photosphere is not a solid layer; if a spaceship (that could withstand the heat) fell through it, it wouldn't feel anything when reaching the photosphere E. The photosphere is the layer where the Sun becomes opaque (you can't see through it)

A. The photosphere is significantly hotter than all the layers of the Sun

Which of the following is NOT a product of the firststep in the p-p chain of nuclear fusion? A. a form of helium B. a form of hydrogen C. a positron D. a deuteron (nucleus of deuterium atom? consists of a proton and a neutron) E. a neutrino

A. a form of helium

We discussed that light sometimes acts like a photon. What is a photon? A. a self-contained "packet" of electro-magnetic energy B. a charged particle in the nucleus of every atom C. you can't fool me. Einstein showed that photons were a mistake - they don't exist. D. a kind of magnetic substance found in reflective minerals E. a kind of sound that is too high frequency for the human ear to hear

A. a self-contained "packet" of electro-magnetic energy

How objects emit light depends on... A. both the object's temperature and density B. the object's density C. the object's temperature D. none of these

A. both the object's temperature and density

When great currents of hot material rise inside the Sun (and cooler material sinks downward), energy is being transferred by a process known as: A. convection B. equilibrium C. conduction D. radiation

A. convection

When blueshift occurs, the perceived wavelength of the wave would A. decrease B. increase C. stay the same

A. decrease

If the "fuel" for nuclear fusion is nuclei of hydrogen, and the Earth's oceans are filled with hydrogen atoms in water all being jostled together, why isn't there a lot of fusion happening in our oceans? A. for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do B. on Earth, only hydrogen that is in deep mines under the Earth is far enough underground for fusion C. the hydrogen in our oceans is the wrong type of hydrogen for fusion D. for hydrogen to fuse, the nuclei must first join together in long chains of atoms E. you can't fool me, hydrogen in the Earth's oceans does undergo fusion; that's what keeps our oceans warm

A. for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do

Using a good pair of binoculars, you observe a section of the sky where there are stars of many different apparent brightnesses. You find one star that appears especially dim. This star looks dim because it is: A. it could be more than one of the above; there is no way to tell which answer is right by just looking at the star B. very far away C. partly obscured by a cloud D. radiating most of its energy in the infrared region of the spectrum E. very low luminosity

A. it could be more than one of the above; there is no way to tell which answer is right by just looking at the star

Measurements show a certain star has a very high luminosity (100,000 x the Sun's) while its temperature is quite cool (3500o K). How can this be? A. it must be quite large in size B. this must be an error in observations; no such star can exist C. it must be brown dwarf and not a regular star D. it must be a main sequence star E. it must be quite small in size

A. it must be quite large in size

Which of the following characteristics of a single star (one that moves through space alone) is it difficult to measure directly? A. its mass B. its temperature C. its apparent brightness D. its chemical composition E. you can't fool me, all of these are quite easy to measure directly

A. its mass

Stars that lie in different places on the main sequence of the H-R diagram differ from each other mainly by having different: A. masses B. radial velocities C. compositions D. ways that they formed E. internal structure

A. masses

Which of the following is a method for measuring the diameter of a star? A. more than one of the above B. getting the light curve of an eclipsing binary star C. measuring the spectrum of a spectroscopic binary D. watching the body of the Moon go across the star E. comparing the color of a star seen high above our heads and then again when it's near the horizon

A. more than one of the above

Which of the following statements about photons is FALSE? A. photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface B. photons always travel at the speed of light C. photons each carry a specific amount of energy D. high energy photons have a high frequency (when thought of as waves) E. a gamma-ray photon carries more energy than a visible light photon

A. photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface

The material inside the Sun is in the form of a A. plasma B. solid C. liquid D. none of the above E. ball of iron atoms

A. plasma

Which of the following is NOT one of the fundamental particles that we find inside atoms? A. positrons B. all four of the above are found in most atoms C. electrons D. neutrons E. protons

A. positrons

When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process? A. radiation B. theoretical modeling C. conduction D. convection E. none of the above

A. radiation

Stars along the main sequence have similar... A. radii B. temperatures C. colors D. luminosities

A. radii

A fashion designer decides to bring out a new line of clothing which reflects the longest wavelength of visible light. What color will these articles of clothing be to the human eye? A. red B. blue C. yellow-green D. violet E. black

A. red

When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum A. red-shifted (shifted toward the red end of the light spectrum) B. blue-shifted (shifted toward the blue or violet end of the light spectrum) C. become darker and darker (like a blackbody) D. yellow-shifted (shifted so all the colors become a little bit yellower) E. you can't fool me, the Doppler effect only applies to motions on Earth, not to the motions of the stars and galaxies

A. red-shifted (shifted toward the red end of the light spectrum)

In a star like the Sun, high temperatures are required to get H (hydrogen) nuclei to fuse because they ____ one another, due to their ____ electric charges. A. repel, positive B. repel, negative C. attract, positive D. attract, negative

A. repel, positive

I am measuring the spectrum of the stars in a spectroscopic binary system. When one of the stars is moving toward the Earth in its orbit, we observe A. that the lines in its spectrum show a blue-shift B. that the lines its spectrum get brighter C. none of the above D. that the lines in its spectrum merge with the lines of the other star E. that it is no longer possible to learn what elements are in the star

A. that the lines in its spectrum show a blue-shift

Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in: A. the ozone layer B. the region between the Earth and the Sun C. the ionosphere D. stratosphere

A. the ozone layer

Most of the really bright stars in our sky are NOT among the stars that are very close to us. Why then do they look so bright to us? A. these stars are intrinsically so luminous, that they can easily be seen even across great distances B. all the brightest stars are red, and red color is much easier to see against the black night sky C. we see them in crowded regions of stars, which give us the impression that the stars there are brighter than they really are D. actually, this is just an optical illusion; all stars are really the same brightness E. these stars vary in brightness (flashing brighter and dimmer) and are thus easier to notice

A. these stars are intrinsically so luminous, that they can easily be seen even across great distances

Sunspots are darker than the regions of the Sun around them because A. they are cooler than the material around them (although still very hot compared to Earth temperatures) B. they are the shadows of the planets and asteroids seen on the bright surface of the Sun C. they move much faster around the Sun than other material and thus heat up D. they consist of different elements than the rest of the Sun E. they are located in the corona and not on the photosphere

A. they are cooler than the material around them (although still very hot compared to Earth temperatures)

Which part of the Sun's atmosphere is the hottest? A.corona B.chromosphere C.transition region D.just above the photosphere E.they are all roughly the same temperature

A.corona

The Sun's chromosphere contains many jet-like projections that stick up into the transition region. These spikes of gas are called: A.spicules B.plages C.coronae D.prominences E.flares

A.spicules

The speed of light is equal to... A. 3x10^11 m/s B. 3x10^8 m/s C. 3x10^11 km/s D. 3x10^8 km/s

B. 3x10^8 m/s

The most common element in the Sun is A. Water B. Hydrogen C. Nitrogen D. Iron E. Helium

B. Hydrogen

Why are line emission spectra of elements called "atomic fingerprints"? A. They all contain colored light B. They are all unique C. They are all similar D. They are all the same

B. They are all unique

Which of the following has the smallest mass? A. a brown dwarf B. a planet C. you can't fool me, all the above have roughly the same mass D. the sun E. the smallest mass star that can still have fusion of hydrogen to helium in its core

B. a planet

A Hertz is A. a unit of velocity B. a unit of frequency C. a unit of wavelength D. a unit of loudness

B. a unit of frequency

In an H-R diagram, where can you see the spectral type of a star (whether it is an O type star or a G type star, for example)? A. H-R diagrams have nothing to say about spectral types B. along the bottom (the horizontal axis) C. only on the main sequence D. along the right (vertical axis) E. only in the red giant region

B. along the bottom (the horizontal axis)

One of your good friends asks you to point out the stars with the smallest mass on an H-R diagram that you are studying. Where are you sure to find the stars with the lowest mass on any H-R diagram? A. among the supergiants B. among the stars at the bottom right of the main sequence C. among the stars at the top left of the main sequence D. among the white dwarfs E. stars with low mass can be located anywhere at all in the H-R diagram

B. among the stars at the bottom right of the main sequence

Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for: A. the reddish color we see during sunsets B. aurorae C. tropical storms D. the greenhouse effect E. the poor quality of television programming in the world's northern hemisphere

B. aurorae

One key difference that astronomers use to distinguish between brown dwarfs and high-mass planets is that: A. brown dwarfs are all much larger in diameter than any planets B. brown dwarfs are able to do deuterium fusion in their cores, while planets can't C. brown dwarfs shine quite brightly in visible light, while planets are only visible from the light they reflect D. brown dwarfs are much lower in mass than planets like Jupiter E. brown dwarfs have a much lower luminosity than any planets

B. brown dwarfs are able to do deuterium fusion in their cores, while planets can't

The hottest zone in the Sun is the A. convective zone B. core C. chromosphere D. photosphere E. radiative zone

B. core

Which of the following statements about the violent events on the Sun called flares is FALSE? A. the visible light we see from a flare is only a tiny fraction of the energy it releases B. flares originate in the upper part of the corona, in the regions called coronal holes C. astronomers think that flares are connected with sudden changes in the magnetic field of the Sun D. a flare can release energy equivalent to a million hydrogen bombs E. flares happen more often during solar maximum, and sometimes during those periods, there can be several in one day

B. flares originate in the upper part of the corona, in the regions called coronal holes

Not all wavelengths of electromagnetic radiation can penetrate the Earth's atmosphere. Of the following types of waves that come from space, which one are you likely to be able to detect most easily from our planet's surface: A. x-rays B. radio waves of the wavelength that carry FM broadcasts C. infrared waves D. ultraviolet waves E. gamma rays

B. radio waves of the wavelength that carry FM broadcasts

Which of the following is a way for astronomers to learn more about the interior of the Sun? A. study the corona during eclipses of the Sun B. study the oscillations (pulsations) of the Sun's surface C. study the accounts in ancient legends of the realm where the devil is supposed to live D. follow the orbit of Mercury, the closest planet to the Sun E. take photographs of the Sun in the light absorbed by hydrogen atoms

B. study the oscillations (pulsations) of the Sun's surface

As you go upwards from the Sun's photosphere, A. the temperature decreases B. the density (number of atoms in a unit volume) decreases C. the layers get easier to see with the unaided eye D. only red light can emerge E. the kinds of atoms present change drastically

B. the density (number of atoms in a unit volume) decreases

Light intensity is dependent on the... A. distance to the emitting object squared B. the inverse of the distance to the emitting object squared C. the inverse of the distance to the emitting object D. distance to the emitting object

B. the inverse of the distance to the emitting object squared

How do astronomers know how strong the magnetic field of the Sun is? A. the diameter of a star is directly related to the size of its magnetic field B. the measure the Zeeman effect (the splitting of spectral lines) C. they count the number of days in the year that we get an aurora in the upper atmosphere D. they measure the Sun's rotation using the Doppler effect E. they measure the magnetic field of the Earth, which is a direct result of the magnetic field of the Sun

B. the measure the Zeeman effect (the splitting of spectral lines)

In the future, several students living on board a space station decide to have a race among different types of electromagnetic radiation. Which of the following travels through space the fastest? A. radio waves B. you can't fool me, all of these travel through space at the same speed C. x-rays D. visible light E. infrared

B. you can't fool me, all of these travel through space at the same speed

Which part of the Sun's atmosphere has the lowest density (number of atoms per unit volume)? A.all of these regions have roughly the same density B.corona C.transition region D.chromosphere E.just above the photosphere

B.corona

A team of astronomers takes spectra of thousands of different stars in different parts of the sky. The spectra show significant differences. The mainreason the spectra of the stars do not all look alike is that the stars A. sometimes have atmospheres and sometimes do not B. have different temperatures C. are made of significantly different elements D. change their spectra as they age, and so young stars have very different spectra from older ones E. are located in many different regions of the Milky Way

C. are made of significantly different elements

How fast do electro-magnetic waves travel? A. at the speed of sound B. at the speed of charge C. at the speed of light D. at different speeds, depending on the temperature of the atoms that produce them E. they always have zero speed

C. at the speed of light

Warmer objects appear A. bluer with a longer wavelength B. redder with a longer wavelength C. bluer with a shorter wavelength D. redder with a shorter wavelength

C. bluer with a shorter wavelength

At an astronomical conference, an astronomer gives a report on a star that interests astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed? A. by seeing how the luminosity of the star has been decreasing as it moves farther and farther away B. the astronomer must be making up stories to impress his colleagues; there is no way to measure the speed with which stars move away or toward us. C. by looking at the Doppler shift in the lines of the star's spectrum D. by measuring the diameter of the star (which is easy to do) and noticing that it is getting smaller and smaller E. by seeing the whole star become much redder than it used to be

C. by looking at the Doppler shift in the lines of the star's spectrum

What causes bright lines on an emission spectrum? A. protons falling to lower energy levels, releasing light B. protons jumping to higher energy levels when absorbing light C. electrons falling to lower energy levels, releasing light D. electrons jumping to higher energy levels when absorbing light

C. electrons falling to lower energy levels, releasing light

The energy of random atomic and molecular motion is called A. reflection B. the doppler shift C. heat D. spectra

C. heat

Stars on the main sequence obey a mass-luminosity relation. According to this relation, A. the brightest stars are made of such light materials they hardly have any mass at all B. bright stars have more mass around them in the form of planets, comets, and asteroids C. luminosity is proportional to mass to the fourth power (luminosity increases strongly with mass) D. if you double the mass, you get double the luminosity E. the lower the mass, the higher the luminosity

C. luminosity is proportional to mass to the fourth power (luminosity increases strongly with mass)

Consider two identical stars. Star A is three times as far away as Star B. Star A therefore appears A. three times dimmer than Star B B. three times brighter than Star B C. nine times dimmer than Star B D. nine times brighter than Star B

C. nine times dimmer than Star B

The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing? A. you can't fool me, the Sun is shrinking all the time, it just happens very slowly B. neutrinos from the core exert an enormous pressure on the layers of the Sun as they travel outward; this pressure is more than enough to keep our star from collapsing C. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced D. the pressure of the corona keeps the Sun's main body of gases confined to a small volume E. the gravity of the planets around the Sun pulls its material outward, preventing collapse

C. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced

Astronomers call the motion of a star across the sky (perpendicular to our line of sight) its A. spectral type B. doppler shift C. proper motion D. radial velocity E. light travel time

C. proper motion

Which part of the Sun has the greatest density? A. the corona B. you can't fool me; all the Sun's parts have the same density C. the core D. the photosphere E. the convection region

C. the core

Which of the following statements about electromagnetic radiation is FALSE? A. it is given off by all objects that are not at a temperature of absolute zero B. it always spreads out at the speed of light C. the radiation consists of tiny charged particles given off by the nuclei of atoms D. different waves of electromagnetic radiation differ in their wavelength or frequency

C. the radiation consists of tiny charged particles given off by the nuclei of atoms

A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument? A. the electrons outside the nucleus repel the protons and keep them inside the nucleus B. the neutrons in the nucleus are negative, so they cancel the positive charge on the protons C. the strong nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together D. gravity is much stronger than electric repulsion and holds every nucleus together E. there is no answer; scientists do not have a clue about how the nucleus manages to keep itself together

C. the strong nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

The light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the: A. frequency B. you can't fool me; in these waves, the distance between crests is zero C. wavelength D. amplitude E. velocity

C. wavelength

Match the type of spectra with their appearance. Continuous spectra = Absorption spectra = Emission spectra = -Dark lines -All colors -Bright lines

Continuous spectra = All colors Absorption spectra = Dark lines Emission spectra = Bright lines

What is reflected light? A. Light created and given off by an object B. Light coming from a distant source C. Light from a only nearby source D. Light bouncing off of an object

D. Light bouncing off of an object

What is emitted light? A. Light coming from a distant source B. Light from a only nearby source C. Light bouncing off of an object D. Light created and given off by an object

D. Light created and given off by an object

We see in the... A. X-Ray B. Infrared C. Ultraviolet D. Optical

D. Optical

You are out on the beach, enjoying the warm sunshine with friends. As you glance up at the Sun (only briefly we hope), the part of the Sun that you can see directly is called its: A. Core B. Corona C. Chromosphere D. Photosphere

D. Photosphere

Which statement about the Sun's rotation is TRUE? A. The Sun rotates only at the equator, where the sunspots are found; the rest of the Sun does not rotate B. The Sun rotates once a day C. The Sun does not rotate; only planets rotate D. The Sun rotates at different rates at different latitudes on the Sun E. Only the atmosphere of the Sun rotates, not the main body of the Sun

D. The Sun rotates at different rates at different latitudes on the Sun

What happens when a high amount of energy is added to an atom? A. Cannot be determined B. The electrons emit light C. The electrons become excited and move towards the ground state D. The electrons become excited and increase their energy state

D. The electrons become excited and increase their energy state

An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called: A. a doppler surface B. a spectrum C. an electromagnetic radiator D. a blackbody

D. a blackbody

What happens as an electron falls from a higher level to a lower level in an atom? A. another electron from the lower level takes its place B. the color of the wave involved shifts to the red C. a photon is absorbed D. a photon is given off E. nothing happens; electrons can only go from a lower level to a higher level

D. a photon is given off

Two stars are giving off electromagnetic radiation. The hotter star will: A. will have a higher average frequency of radiation B. will give off a continuous spectrum of waves C. will radiate energy at more than one wavelength D. all of these E. give off more radiation at all wavelengths

D. all of these

Which of the following statements about spectroscopic binary stars is FALSE? A. some of the lines in the spectrum are double, with the spacing changing over time B. visually we can only see one star C. we can often use the changes in the positions of the spectral lines to measure the radial velocity of the stars in the system D. an analysis of the ways the lines in the spectrum change allows us to calculate the star's distance directly E. we can use the spectrum to determine the sum of the masses of the two stars

D. an analysis of the ways the lines in the spectrum change allows us to calculate the star's distance directly

Why do different types of atoms (elements) give off or absorb different spectral lines? A. because some atoms do not have a ground state, while others have three or four B. in heavier elements, diffraction spreads out the lines that the atom produces, making the colors different C. all elements have the same lines, but they are Doppler shifted by different amounts D. because the spacing of the energy levels is different in different atoms E. in some elements, electrons can only move to odd numbered levels, in others only to even numbered ones

D. because the spacing of the energy levels is different in different atoms

Astronomers arrange the stars into groups called spectral classes (or types) according to the kinds of lines they find in their spectra. These spectral classes are arranged in order of: A. increasing amount of hydrogen B. increasing mass C. you can't fool me, there is no order to the spectral types (that's why the letters are not in alphabetical order) D. decreasing surface temperature E. decreasing distance from us

D. decreasing surface temperature

An emission spectra is created when A. electrons in a warming gas move down to a lower energy level B. electrons in a cooling gas move up to a higher energy level C. electrons in a warming gas move up to a higher energy level D. electrons in a cooling gas move down to a lower energy level

D. electrons in a cooling gas move down to a lower energy level

What causes an atom to absorb light? A. photons take in energy and jump to a higher energy level B. electrons release energy when falling to a lower energy level C. photons release energy when falling to a lower energy level D. electrons take in energy and jump to a higher energy level

D. electrons take in energy and jump to a higher energy level

Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life? A. forming from a reservoir of cosmic material B. dying C. you can't fool me; so many stars are on the main sequence that there is no special stage in a star's life that can be identified with it D. fusing hydrogen into helium in their cores E. letting go of a huge outer layer

D. fusing hydrogen into helium in their cores

The granulation pattern that astronomers have observed on the surface of the Sun tells us that: A. the Sun's surface is made of a thin solid that cracks easily B. the Sun is a lot cooler on the inside than on the outside C. the solar wind must consist of very small (low-mass) particles D. hot material must be rising from the Sun's hotter interior E. the Sun accumulates a lot of dirt and dust because of its large gravity

D. hot material must be rising from the Sun's hotter interior

We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have: A. higher speed B. this can't be determined from the information given C. shorter wavelength D. longer wavelength E. lower speed

D. longer wavelength

Astronomers now realize that active regions on the Sun are connected with A. changes in the gravitational pull of the Sun over different parts of its photosphere B. great tropical storm systems in the Earth's atmosphere C. the absence of sunspots during a solar minimum D. loops of magnetic field emerging from the surface of the Sun E. the dark regions between the bright granulation cells on the photosphere

D. loops of magnetic field emerging from the surface of the Sun

The most common kinds of stars in the Galaxy have A. enormous masses compared to the Sun B. a dozen or more stars in close orbit around them C. diameters thousands of times greater than the Sun's D. low luminosity compared to the Sun E. spectra that show they contain mostly carbon

D. low luminosity compared to the Sun

Astronomers observe a typical star using a telescope and a spectrometer. They will see: A. an emission spectrum B. a Doppler shift C. a continuous spectrum D. more than one of these E. an absorption spectrum

D. more than one of these

Where on the H-R Diagram would we find stars that look red when seen through a telescope? A. only near the left side of the diagram and never near the right B. only near the top of the diagram and never near the bottom C. anywhere in the diagram D. only on the right side of the diagram and never on the left E. only near the bottom of the diagram and never near the top

D. only on the right side of the diagram and never on the left

When we use the light of atoms such as hydrogen and calcium to examine the Sun's outer layers, we can see bright "clouds" in the chromosphere right around the location of sunspots. These bright clouds are given the name: A. active regions B. Zeeman rings C. granules D. plages E. spot umbras

D. plages

We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that: A. the cloud is much hotter than hydrogen on Earth B. the cloud is moving away from us C. none of the these can be concluded from this observation D. the cloud is moving toward us E. the cloud is much cooler than hydrogen on Earth

D. the cloud is moving toward us

If it takes an average of 14 billion years before any proton inside the Sun will undergo fusion, and the Sun is only about 5 billion years old, why do astronomers believe that fusion is going on there now? A. there is no fusion going on inside the Sun, and the fact given in the question is one of the reasons why B. much more fusion takes place in the hot atmosphere of the Sun (where it can happen faster), not deep inside (where fusion is slow) C. fusion begins with particles even lighter than protons, which fuse more easily D. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average E. most of the fusion inside the Sun involves carbon, not protons; carbon fuses much more quickly

D. there are an enormous number of protons inside the Sun, and some of them will fuse much sooner than the average

Who was the astronomer who is the "H" in H-R diagram? A. Huggins B. Hoyle C. Humason D. Hubble E. Hertzsprung

E. Hertzsprung

Why is an absorption spectrum especially useful for astronomers? A. It has bright lines in it which allow astronomers to determine how bright the star is B. It shows that the stars are transparent; we can see right through them C. An absorption spectrum is not useful to astronomers at all. When they see one, it means they cannot learn anything about the stars that produced the annoying absorption. D. It helped astronomers to understand the rainbows we see on Earth after storms E. It has dark lines in it that allow astronomers to determine what elements are in the star

E. It has dark lines in it that allow astronomers to determine what elements are in the star

In recent decades, astronomers discovered stars even cooler than the traditional spectral type M stars recently. Astronomers gave these cool stars a new spectral type, L. If you wanted to go out and find more such type L stars, what kind of instrument would it be smart to use? A. a CCD camera attached to an ultra-violet telescope B. a small visible-light telescope (something even an amateur astronomer or small college might have) C. an x-ray telescope, in orbit above the Earth's atmosphere D. a swimming-pool size vat of commercial cleaning fluid, deep in an abandoned mine E. a sensitive infra-red telescope

E. a sensitive infra-red telescope

Stars that do not have what it takes to succeed as a star (i.e. do not have enough mass to fuse hydrogen into helium at their centers) are called: A. spectroscopic stars B. red giants C. main sequence stars D. extras E. brown dwarfs

E. brown dwarfs

In the Sun, when a positron and an electron collide, they will produce: A. a neutron B. a neutrino C. hydrogen D. a deuteron E. energy in the form of a gamma ray

E. energy in the form of a gamma ray

The Doppler effect produces apparent changes in A. velocity B. amplitude C. acceleration D. loudness E. frequency

E. frequency

Which of the following has the highest frequency? A. ultraviolet waves B. you can't fool me, all these have the same frequency C. visible light D. radio waves E. gamma rays

E. gamma rays

Why can astronomers not measure the diameters of stars directly? A. stars are all in binary systems, and we can only see the combined diameter of both stars B. you can't fool me; measuring the diameter of any star is a relatively easy process C. all stars change their diameters regularly, growing alternately larger and smaller D. stars are so bright, their light burns out all the delicate instruments we would use to measure their diameters E. stars are so far away, we cannot resolve (distinguish) their diameters

E. stars are so far away, we cannot resolve (distinguish) their diameters

Ninety percent of all stars (if plotted on an H-R diagram) would fall into a region astronomers call: A. the white dwarf region B. the twilight zone C. the visual region D. the supergiant region E. the main sequence

E. the main sequence

(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off: A. their size B. their chemical makeup C. their distance from the Earth's center D. their mass E. their temperature

E. their temperature

What mechanisms do astronomers believe is responsible for making the Sun's outer atmosphere so much hotter than its photosphere? A.the ionization of a new element called coronium B.astronomers really don't have even a guess about what heats the Sun's outermost layers C.stirring by comets, meteors, and other pieces of solid material being pulled in by the Sun's strong gravity D.light reflected back from the terrestrial planets E.the Sun's magnetic field interacting with the charged particles that make up the atmosphere

E.the Sun's magnetic field interacting with the charged particles that make up the atmosphere

T or F: Objects can either reflect or emit light.

False

T or F: There are many types of light

True

The total energy a star emits is dependent on...

temperature size