Astronomy quiz question: light-gathering power

Astronomy 210 Quiz 3, Spring Semester 2011
Cuesta College, San Luis Obispo, CA

The light-gathering power of an optical telescope depends on the:
(A) focal length of the eyepiece.
(B) focal length of the primary lens/mirror.
(C) diameter of the eyepiece.
(D) diameter of the primary lens/mirror.
(E) (More than one of the above choices.)

Correct answer: (D)

The amount of light that can be gathered by a telescope depends on the area of the primary lens or mirror, which is set by its physical diameter.

Section 30674
(A) : 0 students
(B) : 5 students
(C) : 3 students
(D) : 31 students
(E) : 3 students

"Success level": 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73
Exam code: quiz03n7uu