How much can we learn about a star from a measurement of its apparent magnitude?
A) its intrinsic brightness (the total light actually emitted by the star)
B) the brightness the star would appear to have if it were exactly 10 pc from Earth
C) the brightness of the star as it appears in Earth's sky
D) the total output of electromagnetic energy emitted at all wavelengths from the star

Question

Quizplus · Accepted Answer

Apparent magnitude measures how bright a star appears from Earth, not its intrinsic brightness or total energy output.

How Much Can We Learn About a Star from a Measurement