In a binary system, the more massive star

In a binary system, the more massive star
 
  a. is at the center of mass.
  b. is farthest from the center of mass.
  c. is nearest the center of mass.
  d. follows the largest orbit.
  e. shows a larger Doppler shift in its spectral lines.

Question 2

A totally eclipsed moon glows coppery red because
 
  a. the moon' surface is made of iron ore which is red in color.
  b. red light is cooler than blue light.
  c. during a lunar eclipse the sun is cooler than normal and its light is more red.
  d. only red light is able to pass completely through Earth's atmosphere and reach the moon.
  e. the moon appears red during a total solar eclipse, not a total lunar eclipse.

Question 3

To determine the orbital period of a visual binary, we must measure
 
  a. brightness.
  b. position on the sky.
  c. wavelengths.
  d. luminosity.
  e. temperature.