Someone on the near side of the Moon would observe Earth rise ...

[Yolanda]

Someone on the near side of the Moon would observe Earth rise once every
 a. 24 hours.
  b. 24 hours and 50 minutes.
  c. 29.5 Earth days.
  d. None of these, the observer would never see Earth rise or set.

Question 2

Unlike spherical mirrors, spherical lenses do not have a focal length equal to ______________.
 Fill in the blank(s) with correct word

[katieost]

Answer to Question 1

d

Answer to Question 2

R/2