Astronomy quiz question: most luminous stars?

Astronomy 210 Quiz 5, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

Which type of main-sequence star is the most luminous?
(A) Low mass (red dwarf).
(B) Medium-mass (sunlike).
(C) Massive.
(D) (This property does not depend on mass.)

Correct answer: (C)

This can be deduced from either the mass-luminosity relationship (luminosity proportional to (mass)^3.5), or by inspection of an H-R diagram, where the upper-left end of the main sequence represents hot, bright, massive stars.

Section 70160
(A) : 1 student
(B) : 1 student
(C) : 31 students
(D) : 1 student

"Success level": 92% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.78