20100204

Astronomy quiz question: sunset/sunrise location

Astronomy 210 Quiz 1, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[Version 1]
On a certain day an observer in San Luis Obispo, CA notices that there are 10 hours between sunrise and sunset. On this day, the sun will set on the horizon at a point:
(A) between northeast and east.
(B) due east.
(C) between east and southeast.
(D) between southwest and west.
(E) due west.
(F) between west and northwest.

Correct answer: (D)

10 hours between sunrise and sunset means winter solstice for San Luis Obispo, CA (or in general for any northern hemisphere location, sometime between autumnal equinoxes and vernal equinoxes), meaning that the sun must rise from south of east, and set south of west.

Section 30674
(A) : 4 students
(B) : 0 students
(C) : 3 students
(D) : 29 students
(E) : 5 students
(F) : 5 students

Success level: 67% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.61

[Version 2]
On a certain day an observer in San Luis Obispo, CA notices that there are 14 hours between sunrise and sunset. On this day, the sun rose on the horizon at a point:
(A) between northeast and east.
(B) due east.
(C) between east and southeast.
(D) between southwest and west.
(E) due west.
(F) between west and northwest.

Correct answer: (D)

14 hours between sunrise and sunset means summer solstice for San Luis Obispo, CA (or in general for any northern hemisphere location, sometime between vernal equinoxes and autumnal equinoxes), meaning that the sun must rise from north of east, and set north of west.

Section 30676
(A) : 39 students
(B) : 9 students
(C) : 9 students
(D) : 8 students
(E) : 2 students
(F) : 6 students

Success level: 53% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.69

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