If star A has an apparent magnitude of 8 while star B has an apparent magnitude of 13,then star A is ________ than star B.
A) 100 times fainter
B) 5 times fainter
C) 5 times brighter
D) 100 times brighter

Question

Quizplus · Accepted Answer

The magnitude scale is logarithmic, meaning that every increase of 1 in magnitude corresponds to a decrease in brightness by a factor of approximately 2.512 (the actual value is 2.512^(1/5)). Thus, the difference in magnitude between star A and star B is 13-8=5, corresponding to a difference in brightness by a factor of 2.512^5, or approximately 100. Since star A has the smaller magnitude (i.e. it is brighter), it must be 100 times brighter than star B. Therefore, the answer is D) 100 times brighter.

If Star a Has an Apparent Magnitude of 8 While