© 2017 Pearson Education, Inc.

Question 1 The visible light we see from our Sun comes from which part? Core Corona Photosphere Chromosphere Convection zone Answer: c © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

Question 2 The density of the Sun is most similar to that of a comet. Jupiter. Earth. interstellar gas. an asteroid. Answer: b © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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. © 2017 Pearson Education, Inc.