Review Clicker Question 9 -s

1. Review Clicker Question 9 -s Test 3The Sun & the Stars

2. Question 9 - 1 a) core b) corona c) photosphere d) chromosphere e) convection zone The visible light we see from our Sun comes from which part?

3. Question 9 - 1 a) core b) corona c) photosphere d) chromosphere e) convection zone The visible light we see from our Sun comes from which part? The photosphere is a relatively narrow layer below the chromosphere and corona, with an average temperature of about 6000 K.

4. Question 9 - 2 a) a comet. b) Jupiter. c) Earth. d) interstellar gas. e) an asteroid. The density of the Sun is most similar to that of

5. Question 9 - 2 a) a comet. b) Jupiter. c) Earth. d) interstellar gas. e) an asteroid. The density of the Sun is most similar to that of The Sun is a ball of charged gas, without a solid surface. Jupiter has a similar composition, but not enough mass to be a star.

6. Question 9 - 3 a) gravity balances forces from pressure. b) the rate of fusion equals the rate of fission. c) radiation and convection balance. d) mass is converted into energy. e) fusion doesn’t depend on temperature. The Sun is stable as a star because

7. Question 9 - 3 a) gravity balances forces from pressure. b) the rate of fusion equals the rate of fission. c) radiation and convection balance. d) mass is converted into energy. e) fusion doesn’t depend on temperature. The Sun is stable as a star because The principle of hydrostatic equilibrium explains how stars maintain their stability.

8. Question 9 - 4 a) carbon (C) into oxygen (O) b) helium (He) into carbon (C) c) hydrogen (H) into helium (He) d) neon (Ne) into silicon (Si) e) oxygen (O) into iron (Fe) The proton–proton cycle involves what kind of fusion process?

9. Question 9 - 4 a) carbon (C) into oxygen (O) b) helium (He) into carbon (C) c) hydrogen (H) into helium (He) d) neon (Ne) into silicon (Si) e) oxygen (O) into iron (Fe) The proton–proton cycle involves what kind of fusion process? In the P-P cycle, four hydrogen nuclei (protons) fuse into one helium nucleus, releasing gamma rays and neutrinos.

10. Question 9 - 5 A neutrino can escape from the solar core within minutes. How long does it take a photon to escape? a) minutes b) hours c) months d) hundreds of years e) about a million years

11. Question 9 - 5 A neutrino can escape from the solar core within minutes. How long does it take a photon to escape? a) minutes b) hours c) months d) hundreds of years e) about a million years Gamma ray photons are absorbed and re-emitted continuously in the layers above the core. They gradually shift in spectrum to visible and infrared light at the photosphere.

12. Question 9 - 6 What is probably responsible for the increase in temperature of the corona far from the Sun’s surface? a) a higher rate of fusion b) the Sun’s magnetism c) higher radiation pressures d) absorption of X rays e) convection currents

13. Question 9 - 6 What is probably responsible for the increase in temperature of the corona far from the Sun’s surface? a) the higher rate of fusion b) the Sun’s magnetism c) higher radiation pressures d) absorption of X rays e) convection currents Apparently the Sun’s magnetic field acts like a pump to increase the speeds of particles in the upper corona.

14. Question 9 - 7 a) every 27 days, the apparent rotation period of the Sun’s surface. b) once a year. c) every 5½ years. d) every 11 years. e) approximately every 100 years. The number of sunspots and solar activity in general peaks

15. Question 9 - 7 a) every 27 days, the apparent rotation period of the Sun’s surface. b) once a year. c) every 5 ½ years. d) every 11 years. e) approximately every 100 years. The number of sunspots and solar activity in general peaks The sunspot cycle shows a consistent 11-year pattern of activity dating back more than 300 years.

16. Question 9 - 8 a) cannot explain how the Sun is stable. b) detect only one-third the number of neutrinos expected by theory. c) cannot detect neutrinos easily. d) are unable to explain how neutrinos oscillate between other types. e) cannot create controlled fusion reactions on Earth. The solar neutrinoproblem refers to the fact that astronomers

17. Question 9 - 8 a) cannot explain how the Sun is stable. b) detect only one-third the number of neutrinos expected by theory. c) cannot detect neutrinos easily. d) are unable to explain how neutrinos oscillate between other types. e) cannot create controlled fusion reactions on Earth. The solar neutrinoproblem refers to the fact that astronomers Further experiments have shown that solar neutrinos can change into other types that were not initially detected.

18. Question 10 - 1 a) sizes of stars. b) distances of stars. c) temperatures of stars. d) radial velocity of stars. e) brightness of stars. Stellar parallax is used to measure the

19. Question 10 - 1 a) sizes of stars. b) distances of stars. c) temperatures of stars. d) radial velocity of stars. e) brightness of stars. Stellar parallax is used to measure the Parallax can be used to measure distances to stars accurately to about 200 parsecs (650 light-years).

20. Question 10 - 2 The angle of stellar parallax for a star gets larger as the a) distance to the star increases. b) size of the star increases. c) size of the telescope increases. d) length of the baseline increases. e) wavelength of light increases.

21. Question 10 - 2 The angle of stellar parallax for a star gets larger as the a) distance to the star increases. b) size of the star increases. c) size of the telescope increases. d) length of the baseline increases. e) wavelength of light increases. Astronomers typically make observations of nearby stars 6 months apart, making the baseline distance equal to 2 AU (Astronomical Units).

22. Question 10 - 3 a) a tennis ball here, and one on the Moon. b) two beach balls separated by 100 city blocks. c) two grains of sand 100 light-years apart. d) two golf balls 100 km apart. e) two baseballs 100 yards apart. You can best model the size and distance relationship of our Sun & the next nearest star using

23. Question 10 - 3 a) a tennis ball here, and one on the Moon. b) two beach balls separated by 100 city blocks. c) two grains of sand 100 light- years apart. d) two golf balls 100 km apart. e) two baseballs 100 yards apart. You can best model the size and distance relationship of our Sun & the next nearest star using The Sun is about one million miles in diameter. The next nearest star is about 25 million times farther away.

24. Question 10 - 4 a) true motion in space. b) apparent shift as we view from opposite sides of Earth’s orbit every six months. c) annual apparent motion across the sky. d) motion toward or away from us, revealed by Doppler shifts. e) orbital motion around the galaxy. A star’s proper motion is its

25. Question 10 - 4 a) true motion in space. b) apparent shift as we view from opposite sides of Earth’s orbit every six months. c) annual apparent motion across the sky. d) motion toward or away from us, revealed by Doppler shifts. e) orbital motion around the galaxy. A star’s proper motion is its A star’s “real space motion” combines its apparent propermotion with its radial motion toward or away from Earth.

26. Question 10 - 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. a) brighter b) hotter c) cooler d) fainter e) more distant

27. Question 10 - 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. a) brighter b) hotter c) cooler d) fainter e) more distant

28. Question 10 - 6 a) distance. b) temperature. c) brightness. d) absolute luminosity. e) radial velocity. A star’s apparent magnitude is a number used to describe how our eyes measure its

29. Question 10 - 6 a) distance. b) temperature. c) brightness. d) absolute luminosity. e) radial velocity. A star’s apparent magnitude is a number used to describe how our eyes measure its

30. Question 10 - 7 a) one million km. b) one Astronomical Unit. c) one light-year. d) ten parsecs. e) ten light-years. The absolute magnitude of a star is its brightness as seen from a distance of

31. Question 10 - 7 a) one million km. b) one Astronomical Unit. c) one light-year. d) ten parsecs. e) ten light-years. The absolute magnitude of a star is its brightness as seen from a distance of Astronomers use a distance of 10 parsecs (about 32 light-years) as a standard for specifying and comparing the brightnesses of stars.

32. Question 10 - 8 Which of the following quantities do you need in order to calculate a star’s luminosity? a) apparent brightness (flux) b) Doppler shift of spectral lines c) color of the star d) distance to the star e) a and d

33. Question 10 - 8 Which of the following quantities do you need in order to calculate a star’s luminosity? a) apparent brightness (flux) b) Doppler shift of spectral lines c) color of the star d) distance to the star e) a and d

34. Question 10 - 9 What are the two important intrinsic properties for classifying stars on an H-R diagram? a) distance and surface temperature b) luminosity and surface temperature c) distance and luminosity d) mass and age e) distance and color

35. Question 10 - 9 What are the two important intrinsic properties for classifying stars on an H-R diagram? a) distance and surface temperature b) luminosity and surface temperature c) distance and luminosity d) mass and age e) distance and color The H–R diagram plots stars based on their luminosities and surface temperatures.

36. Question 10 - 10 a) longer b) more green c) heavier d) shorter e) more constant Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light.

37. Question 10 - 10 a) longer b) more green c) heavier d) shorter e) more constant Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light. Wien’s law states that hotter stars appear more blue in color, and cooler stars appear more red in color.

38. Question 10 - 11 a) its color. b) the pattern of absorption lines in its spectrum. c) Wien’s law. d) differences in brightness as measured through red and blue filters. e) All of the above are used. We estimate the surface temperature of a star by using

39. Question 10 - 11 a) its color. b) the pattern of absorption lines in its spectrum. c) Wien’s law. d) differences in brightness as measured through red and blue filters. e) All of the above are used. We estimate the surface temperature of a star by using

40. Question 10 - 12 a) O b) A c) F d) G e) M Which spectral classification type corresponds to a star like the Sun?

41. Question 10 - 12 a) O b) A c) F d) G e) M Which spectral classification type corresponds to a star like the Sun? The OBAFGKM classification scheme is based on absorption lines.

42. Question 10 - 13 a) apparent brightness. b) direct observation of diameter. c) temperature. d) distance to the star. e) a, b, and c are all true. Astronomers can estimate the size of a star using

43. Question 10 - 13 a) apparent brightness. b) direct observation of diameter. c) temperature. d) distance to the star. e) a, b, and c are all true. Astronomers can estimate the size of a star using Brightness and temperature are used to plot the star on an H–R diagram, and indicate its approximate size. Some stars are large enough to measure directly.

44. Question 10 - 14 a) ages of stars. b) absolute luminosities of stars. c) masses of stars. d) distances to stars. e) rotation rates of stars. Eclipsing binary stars are very useful for determining the

45. Question 10 - 14 a) ages of stars. b) absolute luminosities of stars. c) masses of stars. d) distances to stars. e) rotation rates of stars. Eclipsing binary stars are very useful for determining the Analysis of the lightcurve of an eclipsing binary star system can reveal the masses of the stars.

46. Question 10 - 15 What is the single most important characteristic in determining the course of a star’s evolution? a) density b) absolute brightness c) distance d) surface temperature e) mass

47. Question 10 - 15 What is the single most important characteristic in determining the course of a star’s evolution? a) density b) absolute brightness c) distance d) surface temperature e) mass A star’s mass determines how fast it forms, its luminosity on the main sequence, how long it will shine, and its ultimate fate.

48. Question 11 - 1 a) there are no stars there. b) stars in that direction are obscured by interstellar gas. c) stars in that direction are obscured by interstellar dust. d) numerous black holes capture all the starlight behind them. Some regions of the Milky Way’s disk appear dark because

49. Question 11 - 1 a) there are no stars there. b) stars in that direction are obscured by interstellar gas. c) stars in that direction are obscured by interstellar dust. d) numerous black holes capture all the starlight behind them. Some regions of the Milky Way’s disk appear dark because Dust grains are about the same size as visible light, and they can scatter or block the shorter wavelengths.

50. Question 11 - 2 When a star’s visible light passes through interstellar dust, the light we see a) is dimmed and reddened. b) appears to twinkle. c) is Doppler shifted. d) turns bluish in color. e) ionizes the dust and creates emission lines.