Astronomy quiz question: fusion in the sun's core

Astronomy 210 Quiz 5, spring semester 2012
Cuesta College, San Luis Obispo, CA

Hydrogen fusion in the sun takes place only in the core, because of:
(A) convection currents.
(B) the Doppler effect.
(C) high temperatures and pressures.
(D) degenerate matter.

Correct answer: (C)

Hydrogen fusion in a main-sequence star like the sun requires that the repulsion between protons be overcome by high temperatures (such that the protons have enough speed to come in contact with each other before repelling) and higher pressures (such that there are a lot of proton-proton collisions per time).

Section 30674
Exam code: quiz05nArf
(A) : 2 students
(B) : 1 student
(C) : 28 students
(D) : 1 student

"Success level": 89% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

Section 30676
Exam code: quiz05spH3
(A) : 3 students
(B) : 0 students
(C) : 33 students
(D) : 1 student
(No response: 1 student)

"Success level": 88% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.36