The light-gathering power of a telescope is directly proportional to
A) the area of the primary mirror or lens.
B) the focal length of the primary mirror or lens.
C) the ratio of the focal lengths of its primary mirror or lens and its eyepiece.
D) the length of the telescope tube.
E) the diameter of the eyepiece.

Question

Quizplus · Accepted Answer

The light-gathering power of a telescope is determined by the area of its primary mirror or lens, which is proportional to the square of its diameter. This allows the telescope to collect more light and see fainter objects.

The Light-Gathering Power of a Telescope Is Directly Proportional to