Question 1

Sunspots lie in the photosphere. What influence do they have on the corona above them?

Accepted Answer

A) The magnetic fields arching upward from the sunspot conduct heat to the corona and cause ultraviolet and x-ray emissions from points directly above the sunspots. 
B) The magnetic fields arching upward from the sunspot end directly on coronal holes. 
C) Sunspots block energy from flowing to the corona, so the regions directly above sunspots tend to be cooler and to emit longer wavelengths of infrared. 
D) The chromosphere acts as a shield between the photosphere and the corona, so these two layers do not influence each other. 
A) The magnetic fields arching upward from the sunspot conduct heat to the corona and cause ultraviolet and x-ray emissions from points directly above the sunspots. 
B) The magnetic fields arching upward from the sunspot end directly on coronal holes. 
C) Sunspots block energy from flowing to the corona, so the regions directly above sunspots tend to be cooler and to emit longer wavelengths of infrared. 
D) The chromosphere acts as a shield between the photosphere and the corona, so these two layers do not influence each other.

Question 2

The corona contains very little energy because:

Accepted Answer

A) its temperature is relatively low. 
B) its temperature is high but there are very few atoms. 
C) its temperature is high but the atoms here are relatively large and thus move slowly. 
D) the most energetic particles are carried away by the solar wind, leaving the less energetic behind. 
A) its temperature is relatively low. 
B) its temperature is high but there are very few atoms. 
C) its temperature is high but the atoms here are relatively large and thus move slowly. 
D) the most energetic particles are carried away by the solar wind, leaving the less energetic behind.

Question 3

Where would you expect to find spicules?

Accepted Answer

A) in interstellar clouds heated by hot, massive stars 
B) in supernova remnants 
C) in the atmosphere of the Sun 
D) in binary star systems in which one star is a neutron star attracting and collecting mass from the other 
A) in interstellar clouds heated by hot, massive stars 
B) in supernova remnants 
C) in the atmosphere of the Sun 
D) in binary star systems in which one star is a neutron star attracting and collecting mass from the other

Question 4

What is the nature and extent of the oscillations and waves in the Sun?

Accepted Answer

A) There are many millions of pure "tones" or frequencies. 
B) They have one very specific frequency, the resonant frequency of the Sun, whose period is close to 5 minutes. 
C) There are several billion known frequencies or "tones." 
D) There are now 10 known harmonics of the resonant frequency of the Sun, all at very specific frequencies. 
A) There are many millions of pure "tones" or frequencies. 
B) They have one very specific frequency, the resonant frequency of the Sun, whose period is close to 5 minutes. 
C) There are several billion known frequencies or "tones." 
D) There are now 10 known harmonics of the resonant frequency of the Sun, all at very specific frequencies.

Question 5

What is the dominant mechanism by which energy is transported through the core of the Sun?

Accepted Answer

A) by photons (radiative transport of energy) 
B) by collisions of faster-moving particles with slower-moving particles (conductive transport of energy) 
C) by neutrinos streaming outward through the Sun's material (particle transport of energy) 
D) by hotter gas rising and cooler gas falling (convective transport of energy) 
A) by photons (radiative transport of energy) 
B) by collisions of faster-moving particles with slower-moving particles (conductive transport of energy) 
C) by neutrinos streaming outward through the Sun's material (particle transport of energy) 
D) by hotter gas rising and cooler gas falling (convective transport of energy)

Question 6

The Davis neutrino detection experiment measured only about one-third of the expected solar neutrino flux. The Kamiokande experiment was a great improvement. Why?

Accepted Answer

A) It detected two-thirds of the expected rate. 
B) It was able to detect neutrinos all across the energy spectrum and measured the expected neutrino flux. 
C) It was able to measure the direction of the neutrinos it counted and thus confirm their solar origin. 
D) It was able to detect neutrinos of all three types. 
A) It detected two-thirds of the expected rate. 
B) It was able to detect neutrinos all across the energy spectrum and measured the expected neutrino flux. 
C) It was able to measure the direction of the neutrinos it counted and thus confirm their solar origin. 
D) It was able to detect neutrinos of all three types.

Question 7

What is the source of the solar wind?

Accepted Answer

A) gas flung out from solar flares 
B) gas escaping from x-ray-bright regions of the solar corona 
C) gas flung out from the Sun's equatorial region by the centrifugal force due to the Sun's rotation 
D) gas escaping through coronal holes 
A) gas flung out from solar flares 
B) gas escaping from x-ray-bright regions of the solar corona 
C) gas flung out from the Sun's equatorial region by the centrifugal force due to the Sun's rotation 
D) gas escaping through coronal holes

Question 8

Sound waves on the Sun:

Accepted Answer

A) cannot exist because of the high temperature. 
B) can travel only along the outer surface. 
C) can travel only outward from the core. 
D) travel both inward and outward. 
A) cannot exist because of the high temperature. 
B) can travel only along the outer surface. 
C) can travel only outward from the core. 
D) travel both inward and outward.

Question 9

Compressed magnetic fields tend to push themselves apart. Yet sunspots can be stable for as long as 2 months. How do we explain this?

Accepted Answer

A) Sunspots are stabilized by the circulation of charged gases around the field below the surface of the photosphere. 
B) Sunspots tend to occur in pairs of opposite polarity. The repulsive forces tend to keep each group compressed. 
C) The energy that is needed to push the field lines apart is instead expended in sending spicules into the chromosphere. 
D) The sunspot pairs (preceding and following members) cancel out, relaxing the magnetic fields and their tendency to repel. 
A) Sunspots are stabilized by the circulation of charged gases around the field below the surface of the photosphere. 
B) Sunspots tend to occur in pairs of opposite polarity. The repulsive forces tend to keep each group compressed. 
C) The energy that is needed to push the field lines apart is instead expended in sending spicules into the chromosphere. 
D) The sunspot pairs (preceding and following members) cancel out, relaxing the magnetic fields and their tendency to repel.

Question 10

Most solar variations associated with the so-called solar cycle show a repetitive pattern of magnetic behavior with an approximate period of:

Accepted Answer

A) about 1 year. 
B) 11 years. 
C) 22 years. 
D) 28 days-close to one solar rotation. 
A) about 1 year. 
B) 11 years. 
C) 22 years. 
D) 28 days-close to one solar rotation.

Question 11

The temperature at the center of the Sun, where thermonuclear processes take place, is approximately:

Accepted Answer

A) 4500 K, as shown by holes in the Sun. 
B) 1.5 million K. 
C) 6000 K. 
D) 1.5 × 107 K. 
A) 4500 K, as shown by holes in the Sun. 
B) 1.5 million K. 
C) 6000 K. 
D) 1.5 × 107 K.

Question 12

By how much does the mass of the Sun decrease each second because of the energy it radiates (its luminosity)?

Accepted Answer

A) 4.2 × 109 kg 
B) 3.9 × 1026 kg 
C) 2.0 × 107 kg 
D) 6.0 × 1011 kg 
A) 4.2 × 109 kg 
B) 3.9 × 1026 kg 
C) 2.0 × 107 kg 
D) 6.0 × 1011 kg

Question 13

According to the theoretical model of the Sun tabulated in Table 16-2 and shown graphically in Figure 16-3 of Universe, 11th ed., within what radial distance of the solar center is the vast majority of solar energy generated?
​
  ​

Accepted Answer

A) 0.8 or 80% 
B) 0.25 or 25% 
C) 100%-because energy is generated throughout the whole Sun 
D) 0.60 or 60% 
A) 0.8 or 80% 
B) 0.25 or 25% 
C) 100%-because energy is generated throughout the whole Sun 
D) 0.60 or 60%

Question 14

The density of the Sun decreases as you move outward from the core. Approximately where is the Sun's density equal to the density of water?

Accepted Answer

A) 20% of the way out from the center 
B) 50% of the way out from the center 
C) 80% of the way out from the center 
D) Nowhere. The Sun's density is always greater than that of water. 
A) 20% of the way out from the center 
B) 50% of the way out from the center 
C) 80% of the way out from the center 
D) Nowhere. The Sun's density is always greater than that of water.

Question 15

Sunspots have been observed:

Accepted Answer

A) since at least 2000 years ago. 
B) only since 1610, since they cannot be seen without a telescope. 
C) only since 1859, when special filters were developed. 
D) only in recent decades, since they must be observed from outside Earth's atmosphere. 
A) since at least 2000 years ago. 
B) only since 1610, since they cannot be seen without a telescope. 
C) only since 1859, when special filters were developed. 
D) only in recent decades, since they must be observed from outside Earth's atmosphere.

Question 16

If sunspots are cooler than the photosphere (by at least 1000 K), what will be the peak wavelength in a sunspot spectrum compared with the peak wavelength of the photospheric spectrum?

Accepted Answer

A) the same, because the spectrum still originates on the Sun 
B) either shorter or longer, depending upon the polarity (north or south) of the magnetic field of the spot 
C) longer 
D) shorter 
A) the same, because the spectrum still originates on the Sun 
B) either shorter or longer, depending upon the polarity (north or south) of the magnetic field of the spot 
C) longer 
D) shorter

Question 17

How is sunspot activity on the side of the Sun facing away from Earth monitored?

Accepted Answer

A) We must wait 1 month until that side rotates to face Earth. 
B) This can be done only from a spacecraft on the far side of the Sun. 
C) Sunspots on the far side of the Sun influence the reflection of sound waves toward the near side, where they can be monitored. 
D) Neutrinos reflecting from the sunspots on the far side add to the number reaching Earth. 
A) We must wait 1 month until that side rotates to face Earth. 
B) This can be done only from a spacecraft on the far side of the Sun. 
C) Sunspots on the far side of the Sun influence the reflection of sound waves toward the near side, where they can be monitored. 
D) Neutrinos reflecting from the sunspots on the far side add to the number reaching Earth.

Question 18

In order from highest to lowest, what are the names of the three layers in the Sun's atmosphere?

Accepted Answer

A) photosphere, chromosphere, and corona 
B) photosphere, corona, and chromosphere 
C) chromosphere, photosphere, and corona 
D) corona, chromosphere, and photosphere 
A) photosphere, chromosphere, and corona 
B) photosphere, corona, and chromosphere 
C) chromosphere, photosphere, and corona 
D) corona, chromosphere, and photosphere

Question 19

If the Sun were much less massive, how would the pressure at the center compare to its present value?

Accepted Answer

A) The pressure is unaffected by the mass, so the pressure at the center would be the same as its present value. 
B) The pressure would decrease. 
C) The pressure would increase. 
D) The answer depends on what happens to the radius and thus the resulting density. 
A) The pressure is unaffected by the mass, so the pressure at the center would be the same as its present value. 
B) The pressure would decrease. 
C) The pressure would increase. 
D) The answer depends on what happens to the radius and thus the resulting density.

Question 20

The appearance of the visible spectrum of the Sun, when its light is separated in its component colors, is a:

Accepted Answer

A) uniform continuous spectrum with no structure. 
B) spectrum containing many dark absorption and many bright emission lines on a continuous background. 
C) continuous bright spectrum, crossed by thousands of dark absorption lines. 
D) spectrum consisting only of a few bright emission lines. 
A) uniform continuous spectrum with no structure. 
B) spectrum containing many dark absorption and many bright emission lines on a continuous background. 
C) continuous bright spectrum, crossed by thousands of dark absorption lines. 
D) spectrum consisting only of a few bright emission lines.

Exam 16: Our Star, the Sun

Sunspots lie in the photosphere. What influence do they have on the corona above them?

The corona contains very little energy because:

Where would you expect to find spicules?

What is the nature and extent of the oscillations and waves in the Sun?

What is the dominant mechanism by which energy is transported through the core of the Sun?

The Davis neutrino detection experiment measured only about one-third of the expected solar neutrino flux. The Kamiokande experiment was a great improvement. Why?

What is the source of the solar wind?

Sound waves on the Sun:

Compressed magnetic fields tend to push themselves apart. Yet sunspots can be stable for as long as 2 months. How do we explain this?

Most solar variations associated with the so-called solar cycle show a repetitive pattern of magnetic behavior with an approximate period of:

The temperature at the center of the Sun, where thermonuclear processes take place, is approximately:

By how much does the mass of the Sun decrease each second because of the energy it radiates (its luminosity)?

According to the theoretical model of the Sun tabulated in Table 16-2 and shown graphically in Figure 16-3 of Universe, 11th ed., within what radial distance of the solar center is the vast majority of solar energy generated? ​ ​

The density of the Sun decreases as you move outward from the core. Approximately where is the Sun's density equal to the density of water?

Sunspots have been observed:

If sunspots are cooler than the photosphere (by at least 1000 K), what will be the peak wavelength in a sunspot spectrum compared with the peak wavelength of the photospheric spectrum?

How is sunspot activity on the side of the Sun facing away from Earth monitored?

In order from highest to lowest, what are the names of the three layers in the Sun's atmosphere?

If the Sun were much less massive, how would the pressure at the center compare to its present value?

The appearance of the visible spectrum of the Sun, when its light is separated in its component colors, is a:

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

Gravitation and the Waltz of the Planets

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Asteroids, Comets, and Impacts

The Nature of the Stars

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Evolution: The Death of Stars

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

Filters

According to the theoretical model of the Sun tabulated in Table 16-2 and shown graphically in Figure 16-3 of Universe, 11th ed., within what radial distance of the solar center is the vast majority of solar energy generated?