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2. Question 1
The visible light we see from our Sun comes from which part?
Core
Corona
Photosphere
Chromosphere
Convection zone
Answer: c
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3. Question 1
The visible light we see from our Sun comes from which part?
Core
Corona
Photosphere
Chromosphere
Convection zone
Explanation: The photosphere is a relatively narrow layer below the chromosphere and corona, with an average temperature of about 6000 K.
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4. Question 2 The density of the Sun is most similar to that of a comet.
Jupiter.
Earth.
interstellar gas.
an asteroid.
Answer: b
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5. Question 2 The density of the Sun is most similar to that of a comet.
Jupiter.
Earth.
interstellar gas.
an asteroid.
Explanation: The Sun is a ball of charged gas, without a solid surface. Jupiter has a similar composition, but does not have enough mass to be a star.
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6. Question 3 The Sun is stable as a star because
gravity balances forces from pressure.
the rate of fusion equals the rate of fission.
radiation and convection balance.
mass is converted into energy.
fusion doesn’t depend on temperature.
Answer: a
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7. Question 3 The Sun is stable as a star because
gravity balances forces from pressure.
the rate of fusion equals the rate of fission.
radiation and convection balance.
mass is converted into energy.
fusion doesn’t depend on temperature.
Explanation: The principle of hydrostatic equilibrium explains how stars maintain their stability.
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8. Question 4
The proton–proton cycle involves what kind of fusion process?
Carbon (C) into oxygen (O)
Helium (He) into carbon (C)
Hydrogen (H) into helium (He)
Neon (Ne) into silicon (Si)
Oxygen (O) into iron (Fe)
Answer: c
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9. Question 4
The proton–proton cycle involves what kind of fusion process?
Carbon (C) into oxygen (O)
Helium (He) into carbon (C)
Hydrogen (H) into helium (He)
Neon (Ne) into silicon (Si)
Oxygen (O) into iron (Fe)
Explanation: In the P–P cycle, four hydrogen nuclei (protons) fuse into one helium nucleus, releasing gamma rays and neutrinos.
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10. Question 5
A neutrino can escape from the solar core within minutes. How long does it take a photon to escape?
Minutes
Hours
Months
Hundreds of years
About a million years
Answer: e
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11. Question 5
A neutrino can escape from the solar core within minutes. How long does it take a photon to escape?
Minutes
Hours
Months
Hundreds of years
About a million years
Explanation: Gamma ray photons are absorbed and reemitted continuously in the layers above the core. They gradually shift in spectrum to visible and infrared light at the photosphere.
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12. Question 6
What is probably responsible for the increase in temperature of the corona far from the Sun’s surface?
The higher rate of fusion
The Sun’s magnetism
Higher radiation pressures
Absorption of X-rays
Convection currents
Answer: b
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13. Question 6
What is probably responsible for the increase in temperature of the corona far from the Sun’s surface?
The higher rate of fusion
The Sun’s magnetism
Higher radiation pressures
Absorption of X-rays
Convection currents
Explanation: Apparently, the Sun’s magnetic field acts like a pump to increase the speeds of particles in the upper corona.
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14. Question 7 The number of sunspots and solar activity in general peaks
every 27 days, the apparent rotation period of the Sun’s surface.
once a year.
every 5½ years.
every 11 years.
approximately every 100 years.
Answer: d
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15. Question 7 The number of sunspots and solar activity in general peaks
every 27 days, the apparent rotation period of the Sun’s surface.
once a year.
every 5½ years.
every 11 years.
approximately every 100 years.
Explanation: The sunspot cycle shows a consistent 11-year pattern of activity dating back more than 300 years.
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16. Question 8
The solar neutrino problem refers to the fact that astronomers
cannot explain how the Sun is stable.
detect only one-third the number of neutrinos expected by theory.
cannot detect neutrinos easily.
are unable to explain how neutrinos oscillate between other types.
cannot create controlled fusion reactions on Earth.
Answer: b
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17. Question 8
The solar neutrino problem refers to the fact that astronomers
cannot explain how the Sun is stable.
detect only one-third the number of neutrinos expected by theory.
cannot detect neutrinos easily.
are unable to explain how neutrinos oscillate between other types.
cannot create controlled fusion reactions on Earth.
Explanation: Further experiments have shown that solar neutrinos can change into other types that were not initially detected.
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