Astro 7N Exam 2 UPDATED ACTUAL
Exam Questions and CORRECT Answers
A high luminosity star - CORRECT ANSWER - Emits more light than a low-luminosity
star
If a red giant appears the same brightness as a red main sequence star, which one is farther
away? - CORRECT ANSWER - The red giant
The heaviest nuclei of all are formed... - CORRECT ANSWER - During a supernova
explosion
Hydrogen-2 + proton = ____ + energy: - CORRECT ANSWER - Helium-3
Which of the following has the smallest radius? - CORRECT ANSWER - Neutron star
Why does the main sequence part of a star's life end? - CORRECT ANSWER - The
hydrogen in the core is exhausted.
Which of the following will have the shortest lifetime on the main sequence? - CORRECT
ANSWER - Main sequence star with surface temperature 20000 K
Many of the brightest 100 stars viewed from Earth are not on the main sequence (even though
most stars are) because... - CORRECT ANSWER - The most luminous stars are giants and
supergiants that have already finished their main sequence lifetimes
A 2-solar-mass main sequence star is the same distance as a 0.2-solar-mass main sequence star.
Which star appears brighter? - CORRECT ANSWER - The 2 solar mass main sequence
star appears brighter
,The temperature of the photosphere of the Sun is closest to... - CORRECT ANSWER -
6000 Kelvin
An estimate of the number of communicating/technological civilizations that we expect in our
Galaxy would be a larger number if... - CORRECT ANSWER - The average number of
planets that could support life for each star were larger
If the sun had twice its mass, then which of these planets would be in its habitable zone? -
CORRECT ANSWER - Jupiter
how do astronomers measure the temperature of stars? - CORRECT ANSWER - By
looking at which absorption lines are present in the star's spectrum.
The largest fraction of nearby stars (e.g. within 100 light years) are... - CORRECT
ANSWER - Red main sequence stars
The parallax angle of a nearby star is measured to be 0.02 arcseconds. What is the distance to the
star? - CORRECT ANSWER - 50 parsecs
Which of the following is the sequence of events for a 40-solar mass star (one of the most-
massive stars)? - CORRECT ANSWER - Stellar nursery, protostar, blue star on main
sequence, Type 2 supernova, black hole
Star A is 9 times as luminous as Star B. The two stars appear the same brightness. What is true
about their distance? - CORRECT ANSWER - Star A is 3 times farther away than Star B.
What is the name of the slightly cooler layer of the Sun just outside the photosphere? -
CORRECT ANSWER - Chromosphere
How does a star move on the H-R diagram during the period of time it is converting hydrogen to
helium in its core? - CORRECT ANSWER - It remains nearly fixed at a certain point on
the main sequence and does not move on the H-R diagram.
, If the entire mass of Earth were concentrated in a region the size of a marble, the resulting object
would be... - CORRECT ANSWER - A black hole
Which is the smallest object? - CORRECT ANSWER - A neutron star
A galaxy has an H-alpha emission line observed at a wavelength 10 percent larger than the rest
wavelength of H-alpha. What is the redshift of the galaxy? - CORRECT ANSWER - 0.1
Which is the most luminous? - CORRECT ANSWER - Quasar
Which contains the most stars? - CORRECT ANSWER - A spiral galaxy
Galaxy A appears twice the angular size of Galaxy B. Assuming the two galaxies have the same
physical size in kiloparsecs, which of the following is true? - CORRECT ANSWER -
Galaxy B is 2 times farther away than Galaxy A
What fundamental particles make up a Helium-3 atom? - CORRECT ANSWER - 5 up
quarks, 4 down quarks, 2 electrons
Which statement is FALSE?
A. Planetary nebulae can have layers because of pulsating stars
B. Planetary nebulae usually last tens of thousands of years
C. A planetary nebula will be part of the end state of the Sun
D. Planetary nebulae usually have black holes at their centers
E. Planetary nebulae are a few light years in size - CORRECT ANSWER - D. Planetary
nebulae usually have black holes at their centers
Which statement is true? - CORRECT ANSWER - Stars form in molecular clouds, where
temperature are about 10 Kelvin.
Exam Questions and CORRECT Answers
A high luminosity star - CORRECT ANSWER - Emits more light than a low-luminosity
star
If a red giant appears the same brightness as a red main sequence star, which one is farther
away? - CORRECT ANSWER - The red giant
The heaviest nuclei of all are formed... - CORRECT ANSWER - During a supernova
explosion
Hydrogen-2 + proton = ____ + energy: - CORRECT ANSWER - Helium-3
Which of the following has the smallest radius? - CORRECT ANSWER - Neutron star
Why does the main sequence part of a star's life end? - CORRECT ANSWER - The
hydrogen in the core is exhausted.
Which of the following will have the shortest lifetime on the main sequence? - CORRECT
ANSWER - Main sequence star with surface temperature 20000 K
Many of the brightest 100 stars viewed from Earth are not on the main sequence (even though
most stars are) because... - CORRECT ANSWER - The most luminous stars are giants and
supergiants that have already finished their main sequence lifetimes
A 2-solar-mass main sequence star is the same distance as a 0.2-solar-mass main sequence star.
Which star appears brighter? - CORRECT ANSWER - The 2 solar mass main sequence
star appears brighter
,The temperature of the photosphere of the Sun is closest to... - CORRECT ANSWER -
6000 Kelvin
An estimate of the number of communicating/technological civilizations that we expect in our
Galaxy would be a larger number if... - CORRECT ANSWER - The average number of
planets that could support life for each star were larger
If the sun had twice its mass, then which of these planets would be in its habitable zone? -
CORRECT ANSWER - Jupiter
how do astronomers measure the temperature of stars? - CORRECT ANSWER - By
looking at which absorption lines are present in the star's spectrum.
The largest fraction of nearby stars (e.g. within 100 light years) are... - CORRECT
ANSWER - Red main sequence stars
The parallax angle of a nearby star is measured to be 0.02 arcseconds. What is the distance to the
star? - CORRECT ANSWER - 50 parsecs
Which of the following is the sequence of events for a 40-solar mass star (one of the most-
massive stars)? - CORRECT ANSWER - Stellar nursery, protostar, blue star on main
sequence, Type 2 supernova, black hole
Star A is 9 times as luminous as Star B. The two stars appear the same brightness. What is true
about their distance? - CORRECT ANSWER - Star A is 3 times farther away than Star B.
What is the name of the slightly cooler layer of the Sun just outside the photosphere? -
CORRECT ANSWER - Chromosphere
How does a star move on the H-R diagram during the period of time it is converting hydrogen to
helium in its core? - CORRECT ANSWER - It remains nearly fixed at a certain point on
the main sequence and does not move on the H-R diagram.
, If the entire mass of Earth were concentrated in a region the size of a marble, the resulting object
would be... - CORRECT ANSWER - A black hole
Which is the smallest object? - CORRECT ANSWER - A neutron star
A galaxy has an H-alpha emission line observed at a wavelength 10 percent larger than the rest
wavelength of H-alpha. What is the redshift of the galaxy? - CORRECT ANSWER - 0.1
Which is the most luminous? - CORRECT ANSWER - Quasar
Which contains the most stars? - CORRECT ANSWER - A spiral galaxy
Galaxy A appears twice the angular size of Galaxy B. Assuming the two galaxies have the same
physical size in kiloparsecs, which of the following is true? - CORRECT ANSWER -
Galaxy B is 2 times farther away than Galaxy A
What fundamental particles make up a Helium-3 atom? - CORRECT ANSWER - 5 up
quarks, 4 down quarks, 2 electrons
Which statement is FALSE?
A. Planetary nebulae can have layers because of pulsating stars
B. Planetary nebulae usually last tens of thousands of years
C. A planetary nebula will be part of the end state of the Sun
D. Planetary nebulae usually have black holes at their centers
E. Planetary nebulae are a few light years in size - CORRECT ANSWER - D. Planetary
nebulae usually have black holes at their centers
Which statement is true? - CORRECT ANSWER - Stars form in molecular clouds, where
temperature are about 10 Kelvin.
