Astronomy quiz question: moon phase, two weeks later?

Astronomy 210 Quiz 1, fall semester 2014
Cuesta College, San Luis Obispo, CA

The moon is in its waxing gibbous phase. Which phase will the moon have two weeks later? Clearly circle your answer below.


Correct answer (highlight to unhide): (E)

The moon takes approximately four weeks (a "moonth") to go through its eight phases, such that it will take approximately one week to go through two phases, or approximately two weeks to go through four phases. Thus the moon in its waxing gibbous phase will be in the waning crescent phase two weeks later.

Section 70160
Exam code: quiz01na30
(A) : 5 students
(B) : 2 students
(C) : 3 students
(D) : 3 students
(E) : 16 students
(F) : 1 student
(G) : 4 students
(H) : 2 students

Success level: 45% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.82