Question 1

How do measurements of neutrinos from the sun pose a problem for modern astronomy?

Accepted Answer

The measurements of neutrinos from the s...

Question 2

Some young star clusters contain large numbers of T Tauri stars.

Accepted Answer

A) True 
 B)False

Question 3

What observations reveal star formation in the Orion nebula?

Accepted Answer

The Orion Nebula, also known as M42, is ...

Question 4

The nuclear reactions in a star s core remain under control so long as

Accepted Answer

A)   luminosity depends on mass.
B)   pressure depends on temperature.
C)   density depends on mass.
D)   weight depends on temperature.
E)   temperature depends on mass.

Question 5

The condition of ____________________ means that the force due to gravity pushing down on a layer is exactly equal to the pressure pushing outward on that layer.

Accepted Answer

hydrostati...

Question 6

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Accepted Answer

A) True 
 B)False

Question 7

What observations demonstrate the existence of an interstellar medium?

Accepted Answer

The answer of What observations demonstrate the existence of an...

Question 8

The dust in the interstellar medium can make distant stars look redder than they really are.

Accepted Answer

A) True 
 B)False

Question 9

The lowest mass object that can initiate thermonuclear fusion of hydrogen has a mass of about

Accepted Answer

A)   1 solar masses
B)   80 solar masses
C)   8 solar masses
D)   0.08 solar masses
E)   0.001 solar masses

Question 10

If energy is carried by the bulk motion of matter, that is called ____________________.

Accepted Answer

The answer of If energy is carried by the bulk...

Question 11

____ are small dark nebulae about 1 light-year in diameter that contain 10 to 1,000 solar masses.

Accepted Answer

A)   HI regions
B)   HII regions
C)   Emission nebulae
D)   Bok globules
E)   Reflection nebulae

Question 12

Stars with masses less than ____ produce most of their energy via the proton-proton chain.

Accepted Answer

A)   0.01 solar masses
B)   0.1 solar masses
C)   1.1 solar masses
D)   11 solar masses
E)   110 solar masses

Question 13

The lower edge of the Main Sequence band is known as ____ and represents the location in the HR-diagram at which stars begin their lives as main sequence stars.

Accepted Answer

A)   the Coulomb barrier
B)   hydrostatic equilibrium
C)   the birth line
D)   the zero-age main sequence
E)   the evolutionary track

Question 14

What is the difference between the proton-proton chain and the CNO cycle?

Accepted Answer

The answer of What is the difference between the proton-proton...

Question 15

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photopsheres of stars?

Accepted Answer

Interstellar absorption lines are narrow...

Question 16

The capture of too few solar neutrinos by Davis in the solar neutrino experiment

Accepted Answer

A)   has been disproved by the results of later experiments.
B)   can be explained if the sun is not undergoing thermonuclear fusion of hydrogen in its core.
C)   indicates that the sun s core is much hotter than expected.
D)   indicates that the sun s core is convective.
E)   none of the above

Question 17

Protostars are difficult to observe because

Accepted Answer

A)   the protostar stage is very short.
B)   they are surrounded by cocoons of gas and dust.
C)   they radiate mainly in the infrared.
D)   all of the above
E)   they are all so far away that the light hasn t reached us yet.

Question 18

Opacity is

Accepted Answer

A)   the balance between the pressure and force of gravity inside a star.
B)   the force that binds protons and neutrons together to form a nucleus.
C)   the force that binds an electron to the nucleus in an atom.
D)   a measure of the resistance to the flow of radiation (photons)  through a gas.
E)   the temperature and density at which a gas will undergo thermonuclear fusion.

Question 19

What causes the outward gas pressure that balances the inward pull of gravity in a main sequence star?

Accepted Answer

A)   The rapid outward flow of gas.
B)   The rapid inward flow of the gas.
C)   The high temperature of the gas.
D)   The high density of the gas.
E)   c and d

Question 20

In the proton-proton chain

Accepted Answer

A)   no neutrinos are produced.
B)   energy is released because a hydrogen nucleus has a greater mass than a helium nucleus.
C)   no photons are produced.
D)   carbon serves as a catalyst for the nuclear reaction.
E)   energy is produced in the form of gamma rays and the velocity of the created nuclei.

Exam 10: Structure and Formation of Stars

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Correct AnswerverifiedShow Answer

The lower edge of the Main Sequence band is known as ____ and represents the location in the HR-diagram at which stars begin their lives as main sequence stars.

Correct AnswerverifiedShow Answer

The lowest mass object that can initiate thermonuclear fusion of hydrogen has a mass of about

Correct AnswerverifiedShow Answer

Opacity is

Correct AnswerverifiedShow Answer

Why are interstellar absorption lines so narrow compared to the width of lines which originate in the photopsheres of stars?

Correct AnswerAnswered by ExamLex AIInterstellar absorption lines are narrow...View AnswerShow Answer

The dust in the interstellar medium can make distant stars look redder than they really are.

Correct AnswerverifiedShow Answer

____ are small dark nebulae about 1 light-year in diameter that contain 10 to 1,000 solar masses.

Correct AnswerverifiedShow Answer

The nuclear reactions in a star s core remain under control so long as

Correct AnswerverifiedShow Answer

The condition of ____________________ means that the force due to gravity pushing down on a layer is exactly equal to the pressure pushing outward on that layer.

Correct Answerverifiedhydrostati...View AnswerShow Answer

What causes the outward gas pressure that balances the inward pull of gravity in a main sequence star?

Correct AnswerverifiedShow Answer

Some young star clusters contain large numbers of T Tauri stars.

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How do measurements of neutrinos from the sun pose a problem for modern astronomy?

Correct AnswerAnswered by ExamLex AIThe measurements of neutrinos from the s...View AnswerShow Answer

What is the difference between the proton-proton chain and the CNO cycle?

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Stars with masses less than ____ produce most of their energy via the proton-proton chain.

Correct AnswerverifiedShow Answer

If energy is carried by the bulk motion of matter, that is called ____________________.

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In the proton-proton chain

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What observations demonstrate the existence of an interstellar medium?

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The capture of too few solar neutrinos by Davis in the solar neutrino experiment

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What observations reveal star formation in the Orion nebula?

Correct AnswerAnswered by ExamLex AIThe Orion Nebula, also known as M42, is ...View AnswerShow Answer

Protostars are difficult to observe because

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Interstellar absorption lines are narrow...
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hydrostati...
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The measurements of neutrinos from the s...
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The Orion Nebula, also known as M42, is ...
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