Astronomy quiz question: temperature and fusion

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

[Version 1]

Nuclear fusion is unlikely to occur at room temperature, because nuclei would not move quickly enough to:
(A) break heavy elements apart.
(B) create convection currents.
(C) overcome gravity.
(D) overcome repulsion.

Correct answer: (D)

Atomic nuclei repel each other due to their constituent protons; this repulsion can only be overcome when the nuclei approach each other rapidly enough at temperatures much higher than room temperature.

Note that response (A) refers to nuclear fission.

Section 30674
(A) : 0 students
(B) : 3 students
(C) : 3 students
(D) : 37 students

"Success level": 87% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.24

[Version 2]

Nuclear fusion requires very high temperatures in order for nuclei to move rapidly enough to:
(A) overcome gravity.
(B) overcome repulsion.
(C) break heavy elements apart.
(D) create convection currents.

Correct answer: (B)

Section 30676
(A) : 3 students
(B) : 45 students
(C) : 6 students
(D) : 5 students
(Blank): 2 students

"Success level": 76% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38