## 20160331

### Astronomy quiz question: changing apparent and/or absolute magnitudes of Groombridge 1618

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

Groombridge 1618 is a star that is located 4.87 parsecs away from Earth. If Groombridge 1618 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): (A)

The apparent magnitude of Groombridge 1618, which is the brightness as seen from Earth, will get dimmer as it is moved farther away from 4.87 parsecs to 10 parsecs. The absolute magnitude, which is the intrinsic brightness, will remain the same no matter where Groombridge 1618 is located.

Section 30674
Exam code: quiz05nUL7
(A) : 12 students
(B) : 2 students
(C) : 3 students
(D) : 2 students

Success level: 64% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 1.0