Question 1

What are coronal holes?

Accepted Answer

A)  areas in the corona that allow us to see through to the photosphere
B)  regions in the photosphere where magnetic lines gather, creating cooler areas with much less plasma
C)  tunnels in the outer layers of the Sun that allow photons to escape and form the solar wind
D)  areas of the corona where magnetic field lines project out into space, allowing charged particles to escape and form the solar wind
E)  all of the aboveF) A) and B)
G) A) and C)

Question 2

Based on its surface temperature of 6,000 K, most photons that leave the Sun's surface lie in which region of the electromagnetic spectrum?

Accepted Answer

A)  ultraviolet
B)  microwave
C)  X- ray
D)  visible
E)  infraredF) A) and B)
G) A) and C)

Question 3

Gravitational equilibrium means that the surface and the core of the Sun are at the same pressure.

Accepted Answer

A) True 
 B)False

Question 4

Hydrogen fusion in the Sun requires a temperature (in Kelvin) of

Accepted Answer

A)  billions of degrees.
B)  trillions of degrees.
C)  thousands of degrees.
D)  millions of degrees.
E)  any temperature, as long as gravity is strong enough.F) B) and D)
G) B) and C)

Question 5

Which of the following statements is an inference from a model (rather than an observation) ?

Accepted Answer

A)  The Sun emits neutrinos.
B)  The photosphere emits visible light.
C)  The photosphere is made out of mainly hydrogen and helium.
D)  The corona is hotter than the photosphere.
E)  The Sun's core is gradually turning hydrogen into helium.F) A) and B)
G) None of the above

Question 6

Which of the following quantities is equal to the energy per second generated by the Sun's nuclear reactions?

Accepted Answer

A)  the temperature at the Sun's photosphere
B)  the luminosity of the Sun's photosphere
C)  the force of gravity holding the Sun together
D)  the temperature of the Sun's coreE) B) and D)
F) All of the above

Question 7

Why do sunspots appear dark in pictures of the Sun?

Accepted Answer

A)  They are holes in the solar surface through which we can see through to deeper, darker layers of the Sun.
B)  They actually are fairly bright, but appear dark against the even brighter background of the surrounding photosphere.
C)  They are too cold to emit any visible light.
D)  They are extremely hot and emit all their radiation as X- rays rather than visible light.E) A) and C)
F) B) and D)

Question 8

Energy balance in the Sun refers to a balance between .

Accepted Answer

A)  the amount of energy the Sun radiates into space and the amount of energy that reaches Earth
B)  the rate at which fusion generates energy in the Sun's core and the rate at which the Sun's surface radiates energy into space
C)  the force of gravity pulling inward and the force due to pressure pushing outward
D)  the mass that the Sun loses each second and the amount of mass converted into energy each secondE) B) and C)
F) All of the above

Question 9

What are the appropriate units for the Sun's luminosity?

Accepted Answer

A)  Kilograms
B)  Joules
C)  Watts
D)  NewtonsE) B) and D)
F) B) and C)

Question 10

Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will experience on your journey.

Accepted Answer

First you will experience the light of t...

Question 11

The sun rotates more quickly at the equator than at the poles.

Accepted Answer

A) True 
 B)False

Question 12

When we say that the Sun is a ball of plasma, we mean that _ .

Accepted Answer

A)  the Sun is made of atoms and molecules
B)  the Sun consists of gas in which many or most of the atoms are ionized (missing electrons) 
C)  the Sun is roughly the same color as blood
D)  the Sun is made of material that acts like a liquid acts on EarthE) A) and C)
F) B) and C)

Question 13

What observations characterize solar maximum?

Accepted Answer

A)  There are many sunspots visible on the surface of the Sun.
B)  The Sun emits light of longer average wavelength.
C)  The Sun rotates faster at its poles.
D)  The Sun becomes much brighter.
E)  all of the aboveF) B) and E)
G) A) and B)

Question 14

When the temperature of the Sun's core goes down, what happens next?

Accepted Answer

A)  Fusion reactions slow down; the core expands and heats.
B)  Fusion reactions speed up; the core shrinks and cools.
C)  Fusion reactions slow down; the core shrinks and heats.
D)  Fusion reactions speed up; the core expands and cools.E) A) and D)
F) None of the above

Question 15

Briefly explain how the Sun became hot enough for nuclear fusion.

Accepted Answer

The Sun formed from a cloud of gas. As i...

Question 16

According to this Doppler map of the sun's surface, about how fast is the sun rotating around at its equator?

Accepted Answer

A)  about 20,000 m/s
B)  about 2000 m/s
C)  about 200 m/s
D)  It is not rotating.E) A) and B)
F) A) and D)

Question 17

What is the solution to the solar neutrino problem?

Accepted Answer

A)  Not all fusion reactions create neutrinos.
B)  The Sun is generating energy other than by nuclear fusion.
C)  We did not know how to detect neutrinos.
D)  The electron neutrinos created in the Sun's core change into another type of neutrino that we did not detect.
E)  The Sun is generating much less energy than we think it is.F) A) and C)
G) D) and E)

Question 18

What do sunspots, solar prominences, and solar flares all have in common?

Accepted Answer

A)  They are all strongly influenced by magnetic fields on the Sun.
B)  They all occur only in the Sun's photosphere.
C)  They all have about the same temperature.
D)  They are all shaped by the solar wind.E) None of the above
F) All of the above

Question 19

What is the Sun made of (by mass) ?

Accepted Answer

A)  50% hydrogen, 25% helium, 25% other elements
B)  100% hydrogen and helium
C)  70% hydrogen, 28% helium, 2% other elements
D)  90% dark matter, 10% ordinary matterE) C) and D)
F) None of the above

Question 20

Satellites in low- Earth orbits are more likely to crash to Earth when the sunspot cycle is near solar maximum because .

Accepted Answer

A)  of increased magnetic interference
B)  they are more likely to have their electronics "fried" by a solar flare during solar maximum
C)  Earth's upper atmosphere tends to expand during solar maximum, exerting drag on satellites in low orbits
D)  it is too dangerous to send the Space Shuttle to service satellites during solar maximumE) A) and B)
F) A) and C)

Exam 11: Our Star

Hydrogen fusion in the Sun requires a temperature (in Kelvin) of

Correct AnswerverifiedShow Answer

According to this Doppler map of the sun's surface, about how fast is the sun rotating around at its equator?

Correct AnswerverifiedShow Answer

What observations characterize solar maximum?

Correct AnswerverifiedShow Answer

Gravitational equilibrium means that the surface and the core of the Sun are at the same pressure.

Correct AnswerverifiedShow Answer

Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will experience on your journey.

Correct AnswerverifiedFirst you will experience the light of t...View AnswerShow Answer

What are the appropriate units for the Sun's luminosity?

Correct AnswerverifiedShow Answer

Why do sunspots appear dark in pictures of the Sun?

Correct AnswerverifiedShow Answer

Energy balance in the Sun refers to a balance between .

Correct AnswerverifiedShow Answer

The sun rotates more quickly at the equator than at the poles.

Correct AnswerverifiedShow Answer

When the temperature of the Sun's core goes down, what happens next?

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What are coronal holes?

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Which of the following quantities is equal to the energy per second generated by the Sun's nuclear reactions?

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What is the Sun made of (by mass) ?

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Satellites in low- Earth orbits are more likely to crash to Earth when the sunspot cycle is near solar maximum because .

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Based on its surface temperature of 6,000 K, most photons that leave the Sun's surface lie in which region of the electromagnetic spectrum?

Correct AnswerverifiedShow Answer

Briefly explain how the Sun became hot enough for nuclear fusion.

Correct AnswerverifiedThe Sun formed from a cloud of gas. As i...View AnswerShow Answer

Which of the following statements is an inference from a model (rather than an observation) ?

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What do sunspots, solar prominences, and solar flares all have in common?

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When we say that the Sun is a ball of plasma, we mean that _ .

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What is the solution to the solar neutrino problem?

Correct AnswerverifiedShow Answer

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First you will experience the light of t...
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The Sun formed from a cloud of gas. As i...
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Correct Answer
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