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Astro test 3
| Question | Answer |
|---|---|
| A graduate student has spent a whole year doing a careful analysis of the spectrum of a star. While she has found lines from many elements, there was not a trace of the element helium in the spectra she has been analyzing. From this she can now conclude | since helium shows lines only in hot stars, this star must be relatively cool |
| By which appropriate method the gas density, axial rotation, and magnetic field of a star can be deduced from its spectrum? | Line shape |
| By which appropriate method the chemical composition of a star can be deduced from its spectrum? | Characteristic lines |
| To have a negative ion, you must have: | added an electron to the outer electron shell. |
| Which of the following looks the dimmest in the sky? | a star with magnitude 0.020 |
| An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (rarified) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich | An emission spectrum |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: | Alpha Centauri A (m = -0.01, M = 4.3, spectral class:G, q = 0.742”) |
| Why do different types of atoms (elements) give off or absorb different spectral lines? | Because the spacing of the energy levels is different in different atoms. |
| If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars? | In the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum. |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: Which star is the most luminous? | Sirius |
| Which of the following statements about thermal radiation is always true? | A hot object emits more radio waves than a cool object |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: Which star does look yellowish in color? | Procyon |
| How does the spectrum of a molecule differ from the spectrum of an atom? | Most Adams only have spectral lines at infrared wavelengths. |
| Isotopes of a particular element in the periodic table have which nuclear property in common? | The same number of protons but different numbers of neutrons |
| The astronomer who, at the turn of the century, measured the spectra of hundreds of thousands of stars, leaving a catalog that astronomers used for the rest of the century, was: | Annie CANNON |
| What are the standard units for apparent brightness? | watts per square meter |
| What are the standard units for luminosity? | watts |
| 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? | The total amount of light in the spectrum tells us the stars radius |
| How do astronomers learn what elements are present in a given star? | Look at the absorption lines in its spectrum |
| two stars have the same luminosity, but star B is two times farther away from us than star A. Compared to star A, star B will look | four times fainter |
| After days and days of work, a group of graduate students has finally measured the wavelengths of hundreds of lines in the spectrum of a distant star. If a number of the lines come from molecules such as titanium oxide, the star is likely to be which | M |
| If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet? | the planet is rotating |
| What is the name given to 2/1H? | Deuterium |
| An emission spectrum can be used to identify a(n) | atom |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: HOTTEST | Sirius |
| When white light passes through a cool cloud of gas, we see: | an absorption line spectrum |
| Perhaps the greatest of the Greek astronomers, ________ compiled the first catalog of stars, accurately measured their positions, and defined the basic system of stellar brightnesses | Hipparchus |
| An astronomer studying a particular object in space finds that the object emits light only in specific, narrow emission lines. The correct conclusion is that this object | is made up of a hot, dense gas. |
| The Physical force which holds an atom together is | the electromagnetic attraction between nucleus and electrons. |
| In a visual binary system with circular orbits, if in 20 years the two stars' position angles have shifted by 60 degrees, the pair's period must be: | 240 years |
| Which of the following types of star is the coolest (has the lowest surface temperature)? | M |
| The splitting of spectral lines in the presence of strong magnetic fields is the: | Zeeman effect. |
| The motion of a star across the sky (perpendicular to our line of sight) is called its | proper motion |
| 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 w | The star is moving away from us. |
| In general, the narrower the spectral line of a star: | The bigger the star is |
| In space, positive ions are the result of: | electrons being stripped off the outer electron shell for hot atoms. |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: BRIGHTEST | Sirius |
| The depth of the dip in a star's brightness due to the transit of a planet depends most directly on | the planet's size |
| Thermal radiation is defined as | Radiation that depends only on the emitting objects temperature |
| 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? | The line in the faster rotating star is broader |
| 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 w | The star is moving towards us |
| When an atom absorbs a photon containing energy, any of the following can happen except which? | An electron moves from an upper energy level to a lower one |
| Why are astronomers much more interested in the luminosity of a star than its apparent brightness? | Because the luminosity tells us how bright the start really is, while apparent brightness only tells us how bright it happens to look from Earth |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: LEAST LUMINOUS | Proxima |
| Which of the following statements about electrons is not true? | Electrons ORBIT the nucleus rather like planets orbiting the Sun |
| Light which originates in hydrogen atoms in which electrons have jumped from high levels to the level n = 3 will be part of which series of spectral lines? | Balmer |
| Which of the following can astronomers NOT learn from studying the spectrum of a star? | All of the above can be learned from studying the spectrum |
| Spectra from neutral atoms compared with spectra from ionized atoms of the same element | have different sets of spectral lines. |
| Since the difference in energy between the different rotational states in a molecule is very small, many molecular lines can be observed with | radio or microwave telescopes. |
| When an electron in an atom goes from a higher energy state to a lower energy state, the atom | Emits a photon of a specific frequency |
| Which color star is likely to be the coolest? | red |
| 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? | The galaxy is moving away from you. |
| The Fraunhofer lines in the solar spectrum are actually: | absorption lines due to the thin outer layer above the photosphere. |
| Which of the following statements about spectral types of stars is true? | all of the above are true |
| Which of the following persons used the ideas of quantum mechanics to describe why the spectral classification scheme is in order of decreasing temperature? | cecilia Payne-Gaposchkin |
| The three laws dealing with the creation of various spectra are due to: | Kirchhoff. |
| The most distant stars we can measure stellar parallax for are approximately: | 100 parces away |
| Imagine that a brilliant but quirky scientist in the biology department manages to put you in a deep freeze and you wake up in a million years. Which of the following statements about the sky you would see in that future time is correct? | because of proper motion, a number of the familiar constellations will look somewhat different in a million years |
| The idea that atoms radiate energy only when their electrons move from higher to lower energy levels was first advanced by: | Niels Bohr |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: FAINTEST | Proxima |
| Astronomers have discovered stars even cooler than the traditional spectral type M stars recently. Astronomers have given 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 i | A small visible-light telescope (something even an amateur astronomer or small college might have) |
| In comparing first magnitude Deneb with second magnitude Polaris, we find that: | Deneb appears 2.5 times brighter to us than does Polaris |
| Why are molecular lines more complex than elemental spectral lines? | Molecules can vibrate and rotate as well. |
| At an astronomical conference, an astronomer gives a report on a star that has recently begun to interest 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 mo | By looking at the Doppler shift in the lines of the stars spectrum |
| Atoms in a thin, hot gas (such as a neon advertising sign) emit light | At specific wavelengths, depending upon the element. |
| How much electrical charge does an atom with 11 protons, 12 neutrons, and 10 electrons have? | a positive charge of +1 |
| By which appropriate method the radial velocity of a star can be deduced from its spectrum? | doppler shift |
| What information about an astronomical object can be determined by observing its spectrum? | All of the above |
| If light from a hot, dense star passes through a cool cloud of gas | Only specific wavelengths of light will be removed from the spectrum |
| The Orion Nebula, M-42, is a hot, thin cloud of glowing gas, so its spectrum is: | a few bright lines against a dark background |
| In a spectroscopic binary, if a pair shows a combined set of lines tonight, but a maximum split three nights later, its orbital period must be: | eight days |
| A star with a large parallax: | is at a short distance from Earth. |
| An incandescent light (glowing tungsten filament) produces: | a continuous spectrum, with the peak giving the temperature of the filament. |
| The light from an object moving tangentially (to your left or right) will exhibit: | No shift |
| If one object has a large redshift and another object has a small redshift, what can we conclude about these two objects? | The one with the large redshift is moving AWAY from us FASTER than the one with the small redshift |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: ORANGISH | Arcturus |
| The atomic number which designates the position of an element in the periodic table is equal to | The number of protons in the nucleus of the atom |
| Which of the following terms is given to a pair of stars that we can determine are orbiting each other only by measuring their periodic Doppler shifts? | Visual binary |
| The absolute magnitude of a star is its brightness as seen from a distance of: | 10 light years |
| By which appropriate method the temperature of a star can be deduced from its spectrum? | Spectral Class type |
| An atom of the element cobalt has an atomic number of 27 and an atomic mass number of 59. If it is neutral, how many protons, neutrons, and electrons does it have? | 27 protons, 32 neutrons, 27 electrons |
| Which of the following statements about photons is FALSE? | High energy photons have a high frequency |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: MOST DISTANT | Proxima |
| Which of the following could not be determined by an observation that uses only spectroscopy? | The size of a distant galaxy |
| The apparent magnitudes, the absolute magnitudes, the spectral classes, and the parallaxes of these following stars respectively are: THE COOLEST | Proxima |
| Which of the following terms is given to a pair of stars that appear to change positions in the sky, indicating that they are orbiting one another? | Visual binary |
Created by:
pinstripe