Practice test G

Multiple Choice

Click on the circle in front of the appropriate response. There is only one correct response for each question. Make sure you answer each question.
  1. How can neutrinos be detected?

  2. a. they are visible in radio wavelengths, and can be seen with most radio telescopes
    b. they react with chlorine and these reactions can be measured
    c. they effect the spectral lines of the Sun and cause them to become wider
    d. it is impossible to detect neutrinos

  3. What we see visually as the surface of the Sun is the 

  4. a. photosphere.
    b. chromosphere.
    c. corona.

  5. Sunspots appear dark because they are 

  6. a. cooler than their surroundings.
    b. hotter than their surroundings.
    c. formed on the photosphere.
    d. formed in the chromosphere.

  7. The determination of stellar parallax is important because it allows the direct determination of

  8. a. mass.
    b. distance.
    c. diameter.
    d. velocity.

  9. Which of the following is the correct order for the spectral classification system?

  10. a. OBAFKGM
    b. OBFAGKM
    c. OBAFGKM
    d. ABFGKMO

  11. The observed range of stellar luminosity (in units of solar luminosity) is

  12. a. 1 (they are all the same).
    b. 0.01 to 10.
    c. 0.01 to 100.
    d. 0.0001 to 1,000.
    e. 0.0001 to 1,000,000

  13. Red supergiant stars are in what part of the H-R diagram?

  14. a. high luminosity, high temperature
    b. high luminosity, low temperature
    c. low luminosity, low temperature
    d. low luminosity, high temperature

  15. What physical characteristic of main sequence stars has the widest range of values?

  16. a. mass
    b. luminosity
    c. temperature
    d. radius

  17. The particles which combine during nuclear fusion are

  18. a. electrons and protons.
    b. neutrons and protons.
    c. negatively charged nuclei.
    d. positively charged nuclei.
    e. electrons and neutrons.

  19. A nuclear reaction which occurs at sometime after hydrogen is exhausted in the core is the

  20. a. CNO cycle.
    b. triple alpha reaction.
    c. helium-iron chain.
    d. electron-positron cycle.
    e. tritium-alpha cycle.

  21. The last supernova observed in our galaxy occurred

  22. a. about 40 years ago.
    b. about 400 years ago.
    c. about 4000 years ago.
    d. last week.

  23. What is the main activity occurring in the Orion nebula?

  24. a. supernovae
    b. planetary nebula are forming
    c. star formation
    d. helium flashes

  25. Hydrogen burning for a Sun-like star lasts approximately

  26. a. one million years.
    b. ten million years.
    c. one hundred million years.
    d. one billion years.
    e. ten billion years.

  27. The ignition of helium in the degenerate core of a one solar mass star produces

  28. a. a supernova.
    b. a black hole.
    c. the formation of new heavy elements.
    d. a helium flash.
    e. nothing much - the core expands, cools, and continues burning.

  29. Stars more massive than the Sun obtain their energy while on the main sequence from

  30. a. the proton-proton cycle.
    b. the CNO cycle.
    c. the triple-alpha reaction.
    d. gravitational contraction.

  31. What element is observed in the spectra of Type II supernova?

  32. a. hydrogen
    b. helium
    c. iron
    d. uranium

  33. The observation of __________ from Supernova 1987A proves that our general understanding of how supernovae form is correct.

  34. a. ultraviolet photons
    b. X-ray photons
    c. gamma ray photons
    d. neutrons
    e. neutrinos

  35. As a white dwarf increases in mass (as a result of mass transfer from a companion, for example) 

  36. a. its diameter becomes smaller.
    b. its diameter becomes larger.
    c. its evolution slows down.
    d. its nuclear reactions produce more energy.
    e. it becomes a black dwarf.

  37. If a neutron star's magnetic field were precisely aligned with its rotation axis then 

  38. a. an observer located perpendicular to the rotation axis would see it as a pulsar.
    b. an observer aligned with the rotation axis would see it as a pulsar.
    c. all observers would see it as a pulsar, regardless of their orientation to it.
    d. it would not be observed to be a pulsar.

  39. From the outsider's point of view, in watching a star collapse to form a black hole, the collapse would appear to take

  40. a. only a fraction of a second.
    b. a few hours.
    c. forever.

    Fill In

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  41. An antimatter electron is called a(n) .

  42. The specific temperature of the visible surface of the Sun is K.

  43. Knowledge of a star's parallax allows us to compute its .

  44. The specific nuclear reaction providing energy in the Sun is the .

  45. The thin layer of hot gas just outside the photosphere of the Sun and other cool stars is called the .

  46. A rapid burst of nuclear reactions in the degenerate core of a moderate-mass star in the hydrogen shell-burning phase when the star is a red giant is called the .

  47. The Sun is percent hydrogen.

  48. A star with a main sequence mass of 10 solar masses will most likely end up as a(n) .

  49. A rapidly rotating neutron star that emits periodic bursts of electromagnetic radiation, probably by the emission of beams of radiation from the magnetic poles, is called a(n) .

  50. The region of infinite density and pressure at the center of a black hole is called the .

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