The star Alphard has an apparent magnitude of 2.0,and the star Megrez has an apparent magnitude of 3.3.The only thing that can be said with certainty about Alphard is that it
A) is brighter than Megrez,as seen in our sky.
B) has a greater luminosity than Megrez.
C) is closer than Megrez.
D) is fainter than Megrez,as seen in our sky.

Question

Quizplus · Accepted Answer

Apparent magnitude measures how bright a star appears in our sky, so a star with a lower apparent magnitude appears brighter. Since Alphard has an apparent magnitude of 2.0 and Megrez has an apparent magnitude of 3.3, Alphard is brighter than Megrez. We cannot determine the other options with the given information.

The Star Alphard Has an Apparent Magnitude of 2