20100401

Astronomy quiz question: fusion-generated hydrostatic equilibrium

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

The sun is able to support its weight and maintain a stable size by:
(A) means of strong convection currents.
(B) the radioactive decay of unstable elements.
(C) the resistance to compression of degenerate matter.
(D) generating energy from fusion.

Correct answer: (D)

Hydrostatic equilibrium demands that pressure supports weight, in order for the sun to maintain its stable size; this pressure is generated by the energy released from fusion in its core (as regulated by the pressure-temperature thermostat).

Section 30674
(A) : 3 students
(B) : 0 students
(C) : 6 students
(D) : 34 students

Note that response (B) refers to nuclear fission.

"Success level": 81% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43

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