Astronomy quiz question: changing apparent and/or absolute magnitudes of La Superba

Astronomy 210 Quiz 5, spring semester 2016
Cuesta College, San Luis Obispo, CA

La Superba is a star that is located 320 parsecs away from Earth. If La Superba were moved to a location 10 parsecs away from Earth, its apparent magnitude m would __________, while its absolute magnitude M would __________.
(A) get dimmer; not change.
(B) get brighter; not change.
(C) not change; get dimmer.
(D) not change; get brighter.

Correct answer (highlight to unhide): (B)

The apparent magnitude of La Superba, which is the brightness as seen from Earth, will get brighter as it is moved closer from 320 parsecs to 10 parsecs. The absolute magnitude, which is the intrinsic brightness, will remain the same no matter where La Superba is located.

Section 30676
Exam code: quiz05sPrB
(A) : 4 students
(B) : 41 students
(C) : 1 student
(D) : 5 students

Success level: 81% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.32

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