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Astronomy quiz question: replacing telescope eyepiece

Astronomy 210 Quiz 3, Spring Semester 2009
Cuesta College, San Luis Obispo, CA

The eyepiece of an optical telescope is replaced by an eyepiece with different characteristics. This change affects the __________ of the telescope.
(A) light-gathering power.
(B) resolving power.
(C) magnifying power.
(D) (More than one of the above choices.)

Section 30674
(A) : 1 student
(B) : 6 students
(C) : 19 students
(D) : 12 students

Correct answer: (C)*

The magnification of an optical telescope depends on the ratio of the focal lengths of the primary lens (or mirror) and the eyepiece. The light-gathering power and the resolving power of an optical telescope depend only on the properties of the primary lens (or mirror), specifically the area and diameter, respectively.

"Difficulty level": 52% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38

*Corrected from an earlier typographical error, as per student comment.

1 comment:

Patrick M. Len said...

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

Section 30674
(A) : 4 student
(B) : 7 students
(C) : 24 students
(D) : 6 students
(More than one answer circled): 1 student

"Success level": 61% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64
Exam code: quiz03n7uu