Two identical stars are located at different distances, one star at 2.0 pc and the other at 6.0 pc. How many times greater is the apparent brightness of the nearer star when compared to the more distant one?
A)1.7 times
B)3.0 times
C)9.0 times
D)18 times
E)27 times

Question

Quizplus · Accepted Answer

The apparent brightness of a star is inversely proportional to the square of its distance. Therefore, the brightness ratio is (6.0/2.0)^2 = 9.0 times.

Two Identical Stars Are Located at Different Distances, One Star