_________________ refers to the ability of a telescope to produce bright images. (Fill in the blank)

_________________ refers to the ability of a telescope to produce bright images.
 
  Fill in the blank(s) with correct word

Question 2

The more massive a main-sequence star, the more ___________ it is, as found by the M-L relation.
 
  Fill in the blank(s) with correct word

Question 3

The escape velocity at the event horizon around a black hole is
 
  a. smaller than the speed of light.
  b. equal to the speed of light.
  c. much larger than the speed of light.
  d. irrelevant since nothing (including light) can escape from a black hole.

Question 4

_________________ absorbs most infrared and microwaves coming from outside Earth's atmosphere.
 
  Fill in the blank(s) with correct word