Astronomy quiz question: annular solar eclipse, total lunar eclipse observer locations

Astronomy 210 Quiz 2, fall semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
An annular solar eclipse was observed on May 2012 by observers in Northern California, who were located in:
(A) the moon's umbra.
(B) the moon's penumbra.
(C) the moon's negative shadow.
(D) Earth's umbra.
(E) Earth's penumbra.

Correct answer: (C)

The observers must be located in the moon's antumbra (or "negative shadow") to see the middle of the sun blocked, but the edges still visible.

Section 70158
Exam code: quiz02k3P7
(A) : 12 students
(B) : 10 students
(C) : 5 students
(D) : 5 students
(E) : 2 students
(More than one response) : 1 student

Success level: 19% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.20

[Version 2]
A total lunar eclipse was observed on December 2011 by observers in San Luis Obispo, CA.  During that time, the moon was located in:
(A) Earth's umbra.
(B) Earth's penumbra.
(C) Earth's negative shadow.
(D) (none of Earth's shadow zones.)

Correct answer: (A)

During a total lunar eclipse, the moon is located entirely within Earth's umbra in order for light from the sun to be be completely blocked from reaching the moon (ignoring light scattered by Earth's atmosphere).

Section 70160
Exam code: quiz02n3Ap
(A) : 23 students
(B) : 7 students
(C) : 0 students
(D) : 1 student

Success level: 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.46

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