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ASTRO 7N EXAM 2 QUESTIONS AND ANSWERS
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ASTRO 7N EXAM 2 QUESTIONS AND ANSWERS
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ASTRO 7N EXAM 2 QUESTIONS AND ANSWERSA high-luminosity star...
A. is always at a larger distance than a low-luminosity star
B. emits more light than a low-luminosity star
C. is always redder than a star with a lower luminosity
D. is at a lower temperature than a low-luminosity star
E. is always at a smaller distance than a low-luminosity star - answer - B
If a red giant appears the same brightness as a red main sequence star, which one is
further away?
A. the red giant
B. we cannot tell
C. it depends on the phase of the moon
D. the main sequence star
E. they are at the same distance - answer - A
The heaviest nuclei of all are formed...
A. during helium burning
B. as part of the p-p chain
C. during the carbon burning
D. during supernova explosion
E. during all stages of stellar evolution of massive stars - answer - D
Fill in the blank in the following chemical reaction that occurs in the Sun: Hydrogen-2 +
proton = + energy:
A. hydrogen-2
B. Hydrogen-1
C. Helium-3
D. Carbon-12
E. Helium - 4 - answer - C
Which of the following has the smallest radius?
A. type A main sequence star
B. main sequence star with surface temperature 8000K
C. type K main sequence star
D. white dwarf
E. neutron star - answer - E
Why does the main sequence part of a star's life end?
A. the helium in the core is exhausted
B. the gravitational force is no longer large enough to balance the pressure
C. The hydrogen in the core is exhausted
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D. the temperature drops so that nuclear reactions are no longer possible
E. much of the mass of the star has evaporated - answer - C
Which of the following will have the shortest lifetime on the main sequence?
A. main sequence star with surface temperature 20000K
B. main sequence star with surface temperature 3000K
C. main sequence star with luminosity one tenth that of the sun
D. the sun
E. main sequence star with mass 2 times the sun's - answer - A
Many of the brightest 100 stars viewed from Earth are not on the main sequence (even
though most stars are) because:
A. only high mass stars formed near to us in the Galaxy
B. the most luminous stars are giants and supergiants that have already finished their
main sequence lifetimes.
C. our region of the galaxy is very young
D. the main sequence is the shortest part of a star's life so stars do not spend much
time there
E. our region of the galaxy is very old - answer - B
A 2-solar-mass main sequence star is at the same distance as a 0.2-solar-mass main
sequence star. Which star appears brighter?
A. depends on the phase of the moon
B. the 2 solar mass main sequence star appears brighter
C. the stars are approximately the same brightness
D. the 0.2 solar mass main sequence star appears brighter
E. we cannot tell with the information given - answer - B
The temperature of the photosphere of the sun is closest to...
A. 10^7 Kelvin
B. 10^6 Kelvin
C. 100 kelvin
D. 600,000 kelvin
E. 6,000 kelvin - answer - E
An estimate of the number of communicating / technological civilizations that we expect
in our Galaxy would be a larger number if...
A. the average lifetime of a communicating civilization were smaller
B. the star formation rate in our Galaxy were smaller - answer -
what two gases is the sun mostly composed of? - answer - hydrogen (73%) and helium
(25%)
what makes the sun stable? - answer - balance of gravity (inward force) and gas
pressure in its hot interior (outward force)Powered by TCPDF (www.tcpdf.org)
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