20180913

Astronomy quiz question: morning star Mars?

Astronomy 210 Quiz 2, fall semester 2018
Cuesta College, San Luis Obispo, CA

The locations of Earth, Mars, and Jupiter are shown in the diagram below (not to scale, and orbits have been simplified as circles instead of ellipses).

At sunrise, Mars will be:
(A) low over the east horizon.
(B) somewhere high up in the sky.
(C) low over the west horizon.
(D) not visible in the sky.

Correct answer (highlight to unhide): (D)

If a line is drawn from Earth to the sun, the observer at sunrise (6 AM) is located perpendicular to that line.

Everything below that line would be below the horizon, such that Mars is not visible at sunrise. (Note that Jupiter will also not be visible at sunrise.)

Section 70158
Exam code: quiz02Sl3I
(A) : 7 students
(B) : 3 students
(C) : 4 students
(D) : 22 students

Success level: 62% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.80

Section 70160
Exam code: quiz02N3r1
(A) : 6 students
(B) : 2 students
(C) : 4 students
(D) : 4 students

Success level: 26% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75