Astronomy quiz question: comparing infrared telescope resolutions

Astronomy 210 Quiz 3, fall semester 2015
Cuesta College, San Luis Obispo, CA

In 2004, NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5 m diameter reflecting telescope that was first operated at ground level for testing purposes.[*] If the Hubble Space Telescope's 2.4 m diameter reflecting telescope had also been tested at ground level, it would have made near-infrared observations with _________ amount of resolving power compared to the SOFIA telescope at ground level.
(A) a lesser.
(B) the same.
(C) a greater.
(D) (Not enough information is given.)

[*] sofia.usra.edu/News/releases/pr_2004/OnSky.pdf .

Correct answer (highlight to unhide): (A)

Resolving power depends on the diameter of the primary mirror of a telescope, such that when both making observations at ground level, the Hubble Space Telescope's slightly smaller diameter would have slightly less resolving power compared to the SOFIA telescope, which has a slightly larger diameter and thus slightly more resolving power.

Section 70158
Exam code: quiz03Sss5
(A) : 32 students
(B) : 7 students
(C) : 1 student
(D) : 2 students

Success level: 78% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.36

Section 70160
Exam code: quiz03Nnnn
(A) : 14 students
(B) : 5 students
(C) : 6 students
(D) : 4 students

Success level: 51% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38