Sample Questions

The quiz on Friday, 1/17, will have 10 multiple choice questions, and it will take place during the first 10 minutes of class. Here are eight sample questions that illustrate the type of questions that will be on the quiz.

The parallaxes of nearby stars are produced by

1. the stars' motion across our line of sight
2. the stars' motion along our line of sight
3. the earth's revolution around the sun
4. the rotation of the galaxy
5. the earth's rotation on its axis

If a star has a parallax of one-eighth of a second of arc, it is at a distance of

1. eight parsecs
2. eight light years
3. one-eighth parsec
4. one-eighth light years

The measure of the intrinsic (as opposed to apparent) brightness of a light source is called

1. flux
2. redshift
3. color
4. luminosity

The redder a star is,

1. the larger it must be
2. the smaller it must be
3. the younger it is
4. the lower its surface temperature
5. the denser it is

As we look at the stars hotter than spectral class A, the higher the temperature, the weaker the hydrogen spectral lines. Why?

1. The hydrogen is used to form molecules
2. Very hot stars have converted hydrogen to helium
3. Too much of the hydrogen is ionized
4. All hydrogen atoms have electrons in the first orbit
5. Strong helium lines cover the hydrogen lines

While observing the spectrum of a distant star, an astronomer notices that every few hours each spectral line splits and becomes two. It can be concluded

1. there are really two stars that orbit each other
2. the astronomer has periodic fuzzy vision
3. the star is moving toward the earth
4. the star is pulsating in size

With a typical spectroscopic binary, one cannot learn the masses of the component stars. However, with an eclipsing spectroscopic binary one can find the masses, because

1. The eclipse light curve tells the radii of the stars
2. Eclipsing binaries always have known distances
3. Eclipsing binaries are brighter, yielding better data
4. The eclipse means the orbit must be nearly edge-on
5. The eclipse means one star must be very massive

The Hertzsprung-Russell diagram shows the relation between _________________ of stars.

1. apparent brightness and diameter
2. luminosity and temperature
3. temperature and color
4. mass and luminosity