Question 1

The net result of the proton-proton chain of nuclear reactions is that four protons are converted into one helium nucleus and energy,electrons,and neutrinos are released.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following method(s)is (are)NOT used to transport energy from the core of the Sun to its surface?

Accepted Answer

A) radiation 
B) convection 
C) conduction 
D) All of the above are important in the solar interior. 
E) None of the above are important in the solar interior. 
A) radiation 
B) convection 
C) conduction 
D) All of the above are important in the solar interior. 
E) None of the above are important in the solar interior.

Question 3

If the Sun converts 5 × 1011 kg of H to He per second and the mass of a single hydrogen nucleus is 1.7 × 10−27 kg,how many net proton-proton reactions go on per second in the Sun? What is the luminosity produced if the mass difference between a single helium nucleus and four hydrogen nuclei is 4 × 10−29 kg? Note that 1 Watt = 1 m2 kg/s3.

Accepted Answer

A) 7 × 1037 reactions per sec;3 × 1026 Watt 
B) 3 × 1038 reactions per sec;1027 Watt 
C) 3 × 1038 reactions per sec;4 × 1026 Watt 
D) 7 × 1037 reactions per sec;5 × 1025 Watt 
E) 3 × 1037 ractions per sec;6 × 1024 Watt 
A) 7 × 1037 reactions per sec;3 × 1026 Watt 
B) 3 × 1038 reactions per sec;1027 Watt 
C) 3 × 1038 reactions per sec;4 × 1026 Watt 
D) 7 × 1037 reactions per sec;5 × 1025 Watt 
E) 3 × 1037 ractions per sec;6 × 1024 Watt

Question 4

In addition to the laws of physics and chemistry,what information do we need to know about our Sun to calculate its internal structure and radius?

Accepted Answer

We need to know its

Question 5

The Maunder Minimum was a 60-year period when:

Accepted Answer

A) debris thrown up in a comet collision blanketed the Sun 
B) almost no sunspots occurred on the Sun 
C) the Voyager 2 spacecraft traversed the heliopause 
D) very few dust storms occurred on Mars 
E) very few volcanic eruptions occurred on Mars 
A) debris thrown up in a comet collision blanketed the Sun 
B) almost no sunspots occurred on the Sun 
C) the Voyager 2 spacecraft traversed the heliopause 
D) very few dust storms occurred on Mars 
E) very few volcanic eruptions occurred on Mars

Question 6

The solar magnetic field switches polarity every 11 years.

Accepted Answer

A) True 
 B)False

Question 7

The temperature of the corona is much hotter than any other layer in the solar atmosphere.

Accepted Answer

A) True 
 B)False

Question 8

When is the Sun most luminous?

Accepted Answer

A) when there are a maximum number of sunspots 
B) when there are a average number of sunspots 
C) where there a minimum number of sunspots 
D) the Sun's luminosity does not change 
E) the Sun's luminosity changes,but it has no relation to the number of sunspots 
A) when there are a maximum number of sunspots 
B) when there are a average number of sunspots 
C) where there a minimum number of sunspots 
D) the Sun's luminosity does not change 
E) the Sun's luminosity changes,but it has no relation to the number of sunspots

Question 9

In the text we considered the case of a "too-large" Sun.Show that a star with the same mass,composition,radius,and luminosity as the Sun,but with a higher temperature (that is,a "too-hot" Sun),also leads to a contradiction.

Accepted Answer

If the temperature is higher,more energy

Question 10

At the center of the Sun,the temperature is roughly 15 million K.

Accepted Answer

A) True 
 B)False

Question 11

The detection of solar neutrinos confirms that:

Accepted Answer

A) the Sun's core is powered by proton-proton fusion 
B) energy transport by radiation occurs throughout much of the solar interior 
C) magnetic fields are responsible for surface activity on the Sun 
D) convection churns the base of the solar atmosphere 
E) sunspots are cooler than the rest of the photosphere 
A) the Sun's core is powered by proton-proton fusion 
B) energy transport by radiation occurs throughout much of the solar interior 
C) magnetic fields are responsible for surface activity on the Sun 
D) convection churns the base of the solar atmosphere 
E) sunspots are cooler than the rest of the photosphere

Question 12

If a sunspot is half as bright as the surrounding photosphere of the Sun,what is the approximate temperature of the gas in the sunspot if the photosphere's average temperature is 5800 K?

Accepted Answer

Using the Stefan-Boltzmann law

Question 13

The Sun's chromosphere appears red because:

Accepted Answer

A) it is hotter than the photosphere 
B) as the Sun rotates,the chromosphere appears to move away from us radially 
C) it has a higher concentration of heavy metals 
D) it is made of mostly helium 
E) its spectrum is dominated by Hα emission 
A) it is hotter than the photosphere 
B) as the Sun rotates,the chromosphere appears to move away from us radially 
C) it has a higher concentration of heavy metals 
D) it is made of mostly helium 
E) its spectrum is dominated by Hα emission

Question 14

In our Sun,hydrostatic equilibrium exists only in the core,where energy production via fusion can balance gravity.

Accepted Answer

A) True 
 B)False

Question 15

Which of these can travel directly from the center of the Sun to Earth in about 8 minutes?

Accepted Answer

A) photons 
B) electrons 
C) protons 
D) neutrons 
E) neutrinos 
A) photons 
B) electrons 
C) protons 
D) neutrons 
E) neutrinos

Question 16

Why is hydrogen burning the main energy source for main-sequence stars?

Accepted Answer

A) Hydrogen is the most common element in stars. 
B) Hydrogen nuclei have the smallest positive charge. 
C) Hydrogen burning is the most efficient of all fusion or fission reactions. 
D) Hydrogen can fuse at temperatures lower than other elements. 
E) All the above are valid reasons. 
A) Hydrogen is the most common element in stars. 
B) Hydrogen nuclei have the smallest positive charge. 
C) Hydrogen burning is the most efficient of all fusion or fission reactions. 
D) Hydrogen can fuse at temperatures lower than other elements. 
E) All the above are valid reasons.

Question 17

The surface of the Sun appears sharp when we look at it in visible light because:

Accepted Answer

A) the photosphere is cooler than the layers below it 
B) the photosphere is thin compared to the other layers in the Sun 
C) the photosphere is much less dense than the convection zone 
D) the photosphere is transparent to radiation 
E) the Sun has a distinct surface 
A) the photosphere is cooler than the layers below it 
B) the photosphere is thin compared to the other layers in the Sun 
C) the photosphere is much less dense than the convection zone 
D) the photosphere is transparent to radiation 
E) the Sun has a distinct surface

Question 18

The Sun has a mass of:

Accepted Answer

A) 2 × 1010 kg 
B) 2 × 1025 kg 
C) 2 × 1030 kg 
D) 2 × 1035 kg 
E) 2 × 1045 kg 
A) 2 × 1010 kg 
B) 2 × 1025 kg 
C) 2 × 1030 kg 
D) 2 × 1035 kg 
E) 2 × 1045 kg

Question 19

By studying how the surface of the Sun vibrates like a struck bell we can determine its:

Accepted Answer

A) age 
B) interior density 
C) total mass 
D) size 
E) temperature 
A) age 
B) interior density 
C) total mass 
D) size 
E) temperature

Question 20

Approximately how long does it take the photons released in nuclear reactions in the core of the Sun to exit the photosphere?

Accepted Answer

A) 8 minutes 
B) 16 hours 
C) 1,000 years 
D) 100,000 years 
E) 4.6 billion years 
A) 8 minutes 
B) 16 hours 
C) 1,000 years 
D) 100,000 years 
E) 4.6 billion years

Exam 14: Our Starthe Sun

The net result of the proton-proton chain of nuclear reactions is that four protons are converted into one helium nucleus and energy,electrons,and neutrinos are released.

Which of the following method(s)is (are)NOT used to transport energy from the core of the Sun to its surface?

In addition to the laws of physics and chemistry,what information do we need to know about our Sun to calculate its internal structure and radius?

The Maunder Minimum was a 60-year period when:

The solar magnetic field switches polarity every 11 years.

The temperature of the corona is much hotter than any other layer in the solar atmosphere.

When is the Sun most luminous?

In the text we considered the case of a "too-large" Sun.Show that a star with the same mass,composition,radius,and luminosity as the Sun,but with a higher temperature (that is,a "too-hot" Sun),also leads to a contradiction.

At the center of the Sun,the temperature is roughly 15 million K.

The detection of solar neutrinos confirms that:

If a sunspot is half as bright as the surrounding photosphere of the Sun,what is the approximate temperature of the gas in the sunspot if the photosphere's average temperature is 5800 K?

The Sun's chromosphere appears red because:

In our Sun,hydrostatic equilibrium exists only in the core,where energy production via fusion can balance gravity.

Which of these can travel directly from the center of the Sun to Earth in about 8 minutes?

Why is hydrogen burning the main energy source for main-sequence stars?

The surface of the Sun appears sharp when we look at it in visible light because:

The Sun has a mass of:

By studying how the surface of the Sun vibrates like a struck bell we can determine its:

Approximately how long does it take the photons released in nuclear reactions in the core of the Sun to exit the photosphere?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornments Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

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