Question

QUESTION 1 High-mass stars fuse hydrogen into helium through the CNO cycle rather than solely by the proton-proton chain. Which property of the CNO cycle explains why high mass stars have much shorter lives than low mass stars? a The CNO cycle is very fast at converting hydrogen to carbon, nitrogen, oxygen (CNO). b The CNO cycle is only possible when the abundance of CNO elements is very high. c The CNO cycle is only possible when the star has lived for a very long time. d The CNO cycle is very fast at converting hydrogen to helium. QUESTION 2 Which of the following sequences correctly describes the stages of life (from beginning to end) for a low-mass star? white dwarf, main-sequence, red giant, protostar protostar, main-sequence, white dwarf, red giant protostar, red giant, main-sequence, white dwarf protostar, main-sequence, red giant, white dwarf red giant, protostar, main-sequence, white dwarf QUESTION 3 After a high-mass star explodes in a supernova, what is left behind? always a white dwarf always a neutron star almost always either a white dwarf or a neutron star always a black hole almost always either a neutron star or a black hole QUESTION 4 What happens to a star after it exhausts its core hydrogen? The entire star (both core and outer layers) expands. The entire star (both core and outer layers) contracts. Its core contracts but its outer layers expand. Its core expands but its outer layers contract. QUESTION 5 What change slowly occurs during the main-sequence lifetime of a star? Its core temperature slowly increases, increasing the fusion rate and hence the luminosity. As hydrogen is used up in the core, the fusion rate decreases and reduces the luminosity. It gathers more gas from interstellar space, increasing its mass and hence the luminosity. As the solar wind blows material into space, the decreasing mass reduces pressure in the core, which in turn reduces the fusion rate and the luminosity. QUESTION 6 Which element has the lowest mass per nuclear particle and therefore cannot release energy by either fusion or fission? oxygen uranium iron hydrogen silicon QUESTION 7 What is created by the fusion of three helium nuclei? oxygen iron nitrogen hydrogen carbon QUESTION 8 What happens after the helium flash in the core of a star? The core stops fusing helium. The core quickly heats up and expands as helium fusion begins all at once throughout the core. The star starts to fuse helium in a shell outside the core. The star breaks apart in a violent explosion. The core suddenly contracts because the helium disappears after being fused. QUESTION 9 What happens to the core of a star after a planetary nebula occurs? It breaks apart in a violent explosion. It becomes a neutron star. It can become either a neutron star or a black hole. It becomes a white dwarf. It contracts from a protostar to a main-sequence star. QUESTION 10 Which of the following statements correct describes overall energy balance in a star? Energy in sunspots balances energy in magnetic fields. Energy generated by fusion in the core balances the energy emitted from the star's surface. Gravity balances pressure. Temperature balances light energy emitted at the photosphere. QUESTION 11 How does a red giant compare to a main-sequence star of the same mass? The red giant has lower surface temperature and lower luminosity. The red giant has higher surface temperature and higher luminosity. The red giant lower luminosity but higher surface temperature. The red giant has higher luminosity but lower surface temperature. Both stars have the same mass and therefore have the same surface temperature and luminosity. QUESTION 12 What happens to the core of a star if gravity is strong enough to overcome neutron degeneracy pressure? Gravity is not able to overcome neutron degeneracy pressure. The core contracts and becomes a white dwarf. The core contracts and becomes a black hole. The star explodes violently, leaving nothing behind. The core contracts and becomes a ball of neutrons. QUESTION 13 Which element is the last to be produced by fusion in the cores of the most massive stars (just before their lives end in supernova explosions)? hydrogen lead iron oxygen uranium QUESTION 14 Why are main-sequence lifetimes shorter for more massive stars? More massive stars are made of heavier elements that don't fuse as easily. They aren't; higher mass stars have longer lifetimes. Higher core temperatures allow fusion to proceed much more rapidly. Strong stellar winds cause higher mass stars to lose mass quickly. QUESTION 15 How does a white dwarf compare to a main-sequence star of the same mass? The white dwarf has higher luminosity but lower surface temperature. The white dwarf has lower surface temperature and lower luminosity. The white dwarf has lower luminosity but higher surface temperature. The white dwarf and main-sequence star have the same mass and therefore have the same surface temperature and luminosity. The white dwarf has higher surface temperature and higher luminosity.

Name: question 1 high mass stars fuse hydrogen into helium through the cno cycle rather than solely by the proton proton chain which property of the cno cycle explains why high mass stars have muc 62265
Uploaded: 2021-11-06T00:15:53-08:00
Duration: 5 min 30 s
Channel: Umar Sohail Qureshi
Description: question 1 high mass stars fuse hydrogen into helium through the cno cycle rather than solely by the proton proton chain which property of the cno cycle explains why high mass stars have muc 62265

          QUESTION 1
High-mass stars fuse hydrogen into helium through the CNO cycle
rather than solely by the proton-proton chain. Which property of
the CNO cycle explains why high mass stars have much shorter lives
than low mass stars?
a
The CNO cycle is very fast at converting hydrogen to carbon,
nitrogen, oxygen (CNO).
b
The CNO cycle is only possible when the abundance of CNO
elements is very high.
c
The CNO cycle is only possible when the star has lived for a
very long time.
d
The CNO cycle is very fast at converting hydrogen to helium.

QUESTION 2
Which of the following sequences correctly describes the stages
of life (from beginning to end) for a low-mass star?
white dwarf, main-sequence, red giant, protostar
protostar, main-sequence, white dwarf, red giant
protostar, red giant, main-sequence, white dwarf
protostar, main-sequence, red giant, white dwarf
red giant, protostar, main-sequence, white dwarf

QUESTION 3
After a high-mass star explodes in a supernova, what is left
behind?
always a white dwarf
always a neutron star
almost always either a white dwarf or a neutron star
always a black hole
almost always either a neutron star or a black hole

QUESTION 4
What happens to a star after it exhausts its core hydrogen?
The entire star (both core and outer layers) expands.
The entire star (both core and outer layers) contracts.
Its core contracts but its outer layers expand.
Its core expands but its outer layers contract.

QUESTION 5
What change slowly occurs during the main-sequence lifetime of a
star?
Its core temperature slowly increases, increasing the fusion
rate and hence the luminosity.
As hydrogen is used up in the core, the fusion rate decreases
and reduces the luminosity.
It gathers more gas from interstellar space, increasing its mass
and hence the luminosity.
As the solar wind blows material into space, the decreasing mass
reduces pressure in the core, which in turn reduces the fusion rate
and the luminosity.

QUESTION 6
Which element has the lowest mass per nuclear particle and
therefore cannot release energy by either fusion or fission?
oxygen
uranium
iron
hydrogen
silicon

QUESTION 7
What is created by the fusion of three helium nuclei?
oxygen
iron
nitrogen
hydrogen
carbon

QUESTION 8
What happens after the  helium flash in the core
of a star?
The core stops fusing helium.
The core quickly heats up and expands as helium fusion begins
all at once throughout the core.
The star starts to fuse helium in a shell outside the core.
The star breaks apart in a violent explosion.
The core suddenly contracts because the helium disappears after
being fused.

QUESTION 9
What happens to the core of a star after a  planetary
nebula occurs?
It breaks apart in a violent explosion.
It becomes a neutron star.
It can become either a neutron star or a black hole.
It becomes a white dwarf.
It contracts from a protostar to a main-sequence star.

QUESTION 10
Which of the following statements correct describes
overall  energy balance in a star?
Energy in sunspots balances energy in magnetic fields.
Energy generated by fusion in the core balances the energy
emitted from the star's surface.
Gravity balances pressure.
Temperature balances light energy emitted at the
photosphere.

QUESTION 11
How does a red giant compare to a main-sequence star of the same
mass?
The red giant has lower surface temperature and lower
luminosity.
The red giant has higher surface temperature and higher
luminosity.
The red giant lower luminosity but higher surface
temperature.
The red giant has higher luminosity but lower surface
temperature.
Both stars have the same mass and therefore have the same
surface temperature and luminosity.

QUESTION 12
What happens to the core of a star if gravity is strong enough
to overcome  neutron degeneracy pressure?
Gravity is not able to overcome neutron degeneracy pressure.
The core contracts and becomes a white dwarf.
The core contracts and becomes a black hole.
The star explodes violently, leaving nothing behind.
The core contracts and becomes a ball of neutrons.

QUESTION 13
Which element is the last to be produced by fusion in the cores
of the most massive stars (just before their lives end in supernova
explosions)?
hydrogen
lead
iron
oxygen
uranium

QUESTION 14
Why are main-sequence lifetimes shorter for more massive
stars?
More massive stars are made of heavier elements that don't fuse
as easily.
They aren't; higher mass stars have longer lifetimes.
Higher core temperatures allow fusion to proceed much more
rapidly.
Strong stellar winds cause higher mass stars to lose mass
quickly.

QUESTION 15
How does a white dwarf compare to a main-sequence star of the
same mass?
The white dwarf has higher luminosity but lower surface
temperature.
The white dwarf has lower surface temperature and lower
luminosity.
The white dwarf has lower luminosity but higher surface
temperature.
The white dwarf and main-sequence star have the same mass and
therefore have the same surface temperature and luminosity.
The white dwarf has higher surface temperature and higher
luminosity.

Added by Albert E.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Umar Sohail Qureshi

11/06/2021

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QUESTION 1 High-mass stars fuse hydrogen into helium through the CNO cycle rather than solely by the proton-proton chain. Which property of the CNO cycle explains why high mass stars have much shorter lives than low mass stars? a The CNO cycle is very fast at converting hydrogen to carbon, nitrogen, oxygen (CNO). b The CNO cycle is only possible when the abundance of CNO elements is very high. c The CNO cycle is only possible when the star has lived for a very long time. d The CNO cycle is very fast at converting hydrogen to helium. QUESTION 2 Which of the following sequences correctly describes the stages of life (from beginning to end) for a low-mass star? white dwarf, main-sequence, red giant, protostar protostar, main-sequence, white dwarf, red giant protostar, red giant, main-sequence, white dwarf protostar, main-sequence, red giant, white dwarf red giant, protostar, main-sequence, white dwarf QUESTION 3 After a high-mass star explodes in a supernova, what is left behind? always a white dwarf always a neutron star almost always either a white dwarf or a neutron star always a black hole almost always either a neutron star or a black hole QUESTION 4 What happens to a star after it exhausts its core hydrogen? The entire star (both core and outer layers) expands. The entire star (both core and outer layers) contracts. Its core contracts but its outer layers expand. Its core expands but its outer layers contract. QUESTION 5 What change slowly occurs during the main-sequence lifetime of a star? Its core temperature slowly increases, increasing the fusion rate and hence the luminosity. As hydrogen is used up in the core, the fusion rate decreases and reduces the luminosity. It gathers more gas from interstellar space, increasing its mass and hence the luminosity. As the solar wind blows material into space, the decreasing mass reduces pressure in the core, which in turn reduces the fusion rate and the luminosity. QUESTION 6 Which element has the lowest mass per nuclear particle and therefore cannot release energy by either fusion or fission? oxygen uranium iron hydrogen silicon QUESTION 7 What is created by the fusion of three helium nuclei? oxygen iron nitrogen hydrogen carbon QUESTION 8 What happens after the helium flash in the core of a star? The core stops fusing helium. The core quickly heats up and expands as helium fusion begins all at once throughout the core. The star starts to fuse helium in a shell outside the core. The star breaks apart in a violent explosion. The core suddenly contracts because the helium disappears after being fused. QUESTION 9 What happens to the core of a star after a planetary nebula occurs? It breaks apart in a violent explosion. It becomes a neutron star. It can become either a neutron star or a black hole. It becomes a white dwarf. It contracts from a protostar to a main-sequence star. QUESTION 10 Which of the following statements correct describes overall energy balance in a star? Energy in sunspots balances energy in magnetic fields. Energy generated by fusion in the core balances the energy emitted from the star's surface. Gravity balances pressure. Temperature balances light energy emitted at the photosphere. QUESTION 11 How does a red giant compare to a main-sequence star of the same mass? The red giant has lower surface temperature and lower luminosity. The red giant has higher surface temperature and higher luminosity. The red giant lower luminosity but higher surface temperature. The red giant has higher luminosity but lower surface temperature. Both stars have the same mass and therefore have the same surface temperature and luminosity. QUESTION 12 What happens to the core of a star if gravity is strong enough to overcome neutron degeneracy pressure? Gravity is not able to overcome neutron degeneracy pressure. The core contracts and becomes a white dwarf. The core contracts and becomes a black hole. The star explodes violently, leaving nothing behind. The core contracts and becomes a ball of neutrons. QUESTION 13 Which element is the last to be produced by fusion in the cores of the most massive stars (just before their lives end in supernova explosions)? hydrogen lead iron oxygen uranium QUESTION 14 Why are main-sequence lifetimes shorter for more massive stars? More massive stars are made of heavier elements that don't fuse as easily. They aren't; higher mass stars have longer lifetimes. Higher core temperatures allow fusion to proceed much more rapidly. Strong stellar winds cause higher mass stars to lose mass quickly. QUESTION 15 How does a white dwarf compare to a main-sequence star of the same mass? The white dwarf has higher luminosity but lower surface temperature. The white dwarf has lower surface temperature and lower luminosity. The white dwarf has lower luminosity but higher surface temperature. The white dwarf and main-sequence star have the same mass and therefore have the same surface temperature and luminosity. The white dwarf has higher surface temperature and higher luminosity.