Stars A and B have identical luminosities,but star A is twice as far away as star B.How does the brightness of these two stars compare?
A) Star A is two times brighter than star B.
B) Star A is four times brighter than star B.
C) Star A is two times fainter than star B.
D) Star A is four times fainter than star B.

Question

Quizplus · Accepted Answer

The brightness of a star decreases with the square of the distance from the observer. If star A is twice as far away as star B, its brightness is $1/2^2 = 1/4$ that of star B, making it four times fainter.

Stars a and B Have Identical Luminosities,but Star a Is