The light-gathering power of a telescope depends directly on the
A) area of the final aperture of its eyepiece.
B) focal length of its primary mirror or lens.
C) ratio of the focal lengths of its primary element (mirror or lens) and its eyepiece.
D) area of its primary mirror or lens.

Question

Quizplus · Accepted Answer

The light-gathering power of a telescope is directly related to the area of its primary mirror or lens. A larger primary mirror or lens can collect more light from distant objects, making them appear brighter through the telescope. This is because the amount of light that a telescope can collect is proportional to the square of the diameter of its primary aperture.

The Light-Gathering Power of a Telescope Depends Directly on the