Fall 2000 ASTR 1120-001 Quiz 2

Choose the single best answer and enter it on your scantron form. Be sure to fill in your name and student number.

1. The absolute temperature of an object is a measure of:
   (a) how hot it feels to the touch; (b) its speed; (c) its pressure; (d) how close the object is to thermodynamic equilibrium. (e) the average energy per particle of random jostling motions of its particles.

2. What profound new idea did Arthur Eddington have that revolutionized our concept of the Sun?
   (a) that the Sun is the center of the Solar System; (b) that mass and energy are equivalent; (c) that the interior of the Sun is an ionized plasma, which is compressible like a gas; (d) that the Sun is made of hydrogen; (e) that the Sun is a star.

3. What stops the Sun from collapsing under its own weight?
   (a) the gas pressure of ionized atoms and electrons; (b) its oceans of liquid hydrogen and helium; (c) its rocky core; (d) the fact that hydrogen and helium are so light; (e) gravity.

4. The primary source of the Sun's energy today is:
   (a) chemical; (b) nuclear fission; (c) nuclear fusion; (d) gravitational contraction; (e) a black hole at its center.

5. The source of energy that allowed the Sun to heat up enough to begin burning fuel was:
   (a) chemical; (b) nuclear fission; (c) nuclear fusion; (d) gravitational contraction; (e) a black hole at its center.

6. The lines in the spectrum of an object moving away from you appear:
   (a) redshifted to longer wavelengths; (b) blueshifted to shorter wavelengths; (c) fuzzier; (d) reversed; (e) unchanged.

7. Helioseismology, the study of waves on the surface of the Sun, tells astronomers:
   (a) the temperature of the Sun's surface; (b) about storms on the Sun's surface; (c) about comets and asteroids hitting the Sun; (d) about conditions in the interior of the Sun; (e) about earthquakes on Earth.

8. The Sun's spectrum is best described as:
   (a) a Planck spectrum; (b) a Planck spectrum with many absorption lines; (c) a Planck spectrum with many emission lines; (d) an emission line spectrum; (e) a flat spectrum, equally bright at all wavelengths.

9. Annie Jump Cannon rearranged the spectral types of stars into the sequence OBAFGKM. Cecilia Payne-Gaposchkin subsequently showed that this sequence represented a sequence of:
   (a) mass; (b) radius; (c) age; (d) surface temperature; (e) composition.

10. Besides the Sun, the brightest star (not planet) in the sky is:
    (a) Venus; (b) a Cen; (c) Polaris; (d) Sirius; (e) Sagittarius.