Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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Most
of the light emitted by the Sun comes from the ____. a. | chromosphere | c. | photosphere | b. | corona | d. | prominence | | | | |
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2.
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When
the polarity of the Sun's magnetic field is taken into account, the solar activity cycle lasts
____. a. | 22.4
years | c. | 11.2
years | b. | 22.2 years | d. | 11.4 years | | | | |
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3.
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What
causes the dark bands observed in a solar spectrum? a. | the emission of
specific elements | b. | different chemical elements which absorb light at specific
wavelengths | c. | highly compressed, glowing gas | d. | warmer gas in
front of a source that emits a continuous spectrum | | |
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4.
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The
apparent shift in a stars position caused by the motion of the observer is called
____. a. | luminosity | c. | absolute
magnitude | b. | apparent magnitude | d. | parallax | | | | |
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5.
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A
star that is gravitationally bound to another star can either be part of a star cluster or a ____
star. a. | constellation | c. | binary | b. | white dwarf | d. | red giant | | | | |
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6.
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All
stars, including the Sun, have the following identical composition: a. | 25 percent
hydrogen; 73 percent helium; and 2 percent oxygen | b. | 25 percent
helium; 73 percent hydrogen; and 2 percent other | c. | 25 percent
helium; 73 percent hydrogen; and 2 percent oxygen | d. | 25 percent
hydrogen; 73 percent helium; and 2 percent other | | |
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7.
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The
____ of a star determines its temperature, luminosity, and diameter. a. | mass | c. | energy
output | b. | composition | d. | density | | | | |
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8.
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Only
ten percent of a star's mass undergoes fusion because temperatures outside of the core
____. a. | never get hot
enough for reactions to occur | b. | are too hot for reactions to occur | c. | are too
dependent on the amount of hydrogen | d. | are always changing and are never
stable | | |
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9.
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Following the end of each reaction stage, a massive star becomes a ____ several
times. a. | white
dwarf | c. | main sequence
star | b. | red
giant | d. | supernova | | | | |
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10.
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The
main sequence lifetime of a low-mass star is ____ the lifetime of the Sun. a. | much longer
than | b. | much shorter
than | c. | the same
as | d. | sometimes
identical, sometimes different than | | |
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Matching
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Match each item with the correct definition below. a. | black
hole | e. | main
sequence | b. | photosphere | f. | nebula | c. | fusion | g. | solar activity
cycle | d. | constellation | h. | spectrum | | | | |
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11.
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Combining of lightweight nuclei into heavier nuclei, such as four hydrogen nuclei
combining to form a helium nucleus
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12.
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Cloud
of interstellar gas and dust that collapses on itself to form a new star
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13.
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Visible light arranged according to wavelengths
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14.
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Group
of bright stars named for an animal, a mythological character, or an everyday object
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15.
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Minimum to maximum sunspots, a reversal of polarity, and minimum to maximum sunspots
over a period of 22.4 years
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16.
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Lowest layer of the Suns surface from which most of the light emitted by the Sun
comes
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17.
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Section of the H-R diagram into which about 90 percent of stars fall
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18.
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Small, massive, dense object that has a gravity so immense that nothingnot even
lightcan escape it
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Short Answer
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19.
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On
the H-R diagram shown below, fill out the horizontal axis with the correct spectral types and label
the Sun and main sequence.
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Identify and describe each kind of spectrum and explain how each is
produced.
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20.
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Figure 1 is a(n) ____ spectrum
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Wavelength Shifts
One of the many ways scientists learn more about stars
is the use of spectral lines. They help scientists determine the speed of a stars motion.
Motion between the source of light and the observer cause the spectral lines to shift in wavelength.
Depending on whether the wavelength is shorter or longer, the observer can determine if the star is
moving toward or away from Earth. These shifts are called blueshifts and redshifts. The larger the
shift, the higher the speed of motion. The shifts in spectral lines can also be used to detect binary
stars as they orbit around their center of mass and move toward and away from Earth.
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21.
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The
shifts in spectral lines are an example of the Doppler effect. What motion will this effect not
detect?
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Under
the right conditions, when the CME arrived at Earths magnetosphere, energy would be released in
the form of an intense auroral display. For an intense auroral display, the emission must encounter
Earths magnetic field directly, as opposed to a glancing blow, and the magnetosphere must
already have stored energy, ready to be released in the form of an aurora.
During an aurora, the sky glows as charged particles rain down from
space along Earths magnetic field lines. The resulting color depends on the type of molecules
that the charged particles hit. Energetic particles striking oxygen molecules at an altitude of about
320 km cause all-red auroras. Oxygen at lower altitudes, about 100 km high, produce brilliant
yellow-green colors. These are the brightest and most common auroras. Ionized nitrogen gives off blue
light, and neutral nitrogen glows red. The nitrogens create the purplish-red lower borders and ripple
edges seen in many auroras. Auroras are at least 60 km above Earth and can extend about 1000 km above
the planet. The best places to see an aurora borealis display include Fairbanks, Alaska, parts of
eastern Canada, Iceland, and the Scandinavian countries. These sites are close to the average auroral
oval around Earths north magnetic pole. It is best to see an auroral display during the hours
of local midnight. The farther south, the less chance of seeing an aurora borealis display, but
displays have been seen as far south as Florida and Texas.
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22.
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What
is an aurora, and what two conditions must be present for an intense auroral display?
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23.
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What
colors can an auroral display be? What causes these different colors?
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