Astronomy quiz question: equinox months

Astronomy 210 Quiz 3, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA will notice that there are 12 hours between sunrise and sunset in:
(A) March.
(B) June.
(C) September.
(D) December.
(E) (More than one of the above choices.)

Correct answer: (E)

The vernal and autumnal equinoxes (12 hours daylight/12 hours night) occur in March and in September. Note that an unexpected number of students selected June (summer solstice, 14 hours daylight/10 hours night).

Section 30676
(A) : 4 students
(B) : 25 students
(C) : 2 students
(D) : 1 student
(E) : 43 students
(Blank: 1 student)

"Success level": 61% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.71