Astronomy quiz question: same luminosity as, but hotter/cooler than a G5 giant?

Astronomy 210 Quiz 5, fall semester 2013
Cuesta College, San Luis Obispo, CA

[Version 1]
A G5 giant has the same luminosity and a hotter surface temperature compared to a:
(A) M2 giant.
(B) G5 white dwarf.
(C) B7 main-sequence star.
(D) G5 supergiant.

Correct answer (highlight to unhide): (A)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. The G5 giant has the same luminosity as the B7 main-sequence star and the M2 giant (being on the same horizontal line). The G5 giant is hotter than the M2 giant, while the G5 giant is cooler than the B7 main-sequence star. (Note that the G5 giant has the same temperature as, but a higher luminosity than the G5 white dwarf; and the G5 giant has the same temperature as, but a lower luminosity than a G5 supergiant.)


Section 70158
Exam code: quiz05GieH
(A) : 23 students
(B) : 6 students
(C) : 14 students
(D) : 4 students

Success level: 52% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64

[Version 2]
A G5 giant has the same luminosity and a cooler surface temperature compared to a:
(A) M2 giant.
(B) G5 white dwarf.
(C) B7 main-sequence star.
(D) G5 supergiant.

Correct answer (highlight to unhide): (C)

Section 70160
Exam code: quiz05Nuhl
(A) : 2 students
(B) : 3 students
(C) : 16 students
(D) : 6 students

Success level: 56% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 1.00