Astronomy quiz question: hottest/coolest star

Astronomy 210 Quiz 4, fall semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
Which star is the hottest?
(A) F5 supergiant.
(B) K8 giant.
(C) A0 main sequence star.
(D) G2 white dwarf.

Correct answer: (C)

Using the OBAFGKM spectral type mnemonic, or reading off of an H-R diagram (provided on this quiz), the A0 main-sequence star is the hottest, followed by the F5 supergiant, G2 white dwarf, and K8 giant.

Section 70158
Exam code: quiz04Spr6
(A) : 5 students
(B) : 3 students
(C) : 23 students
(D) : 4 students

Success level: 67% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.78

[Version 2]
Which star is the coolest?
(A) F5 supergiant.
(B) K8 giant.
(C) A0 main sequence star.
(D) G2 white dwarf.

Correct answer: (B)

Section 70160
Exam code: quiz04nNm5
(A) : 1 student
(B) : 19 students
(C) : 2 students
(D) : 4 students

Success level: 74% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43