Question

The sun is a medium-size star with average luminosity and temperature. Which statement describes the relationship between two stars if their apparent magnitude is the same? A. The luminosities must be the same. B. The luminosities and distances can both be different. C. The distances from us must be the same. D. The luminosities and distances must be the same.

Answer 1

Apparent magnitude of a star is indicative of the brightness of that star from a specific distance. Two stars can have the same apparent magnitude from the Earth if both of them have same luminosity and if both of them are situated at the same distance from Earth. When the two stars are present at different distances from the Earth, the apparent magnitude can be same if the luminosity varies, for example a star close to the Earth with a relatively lower luminosity may appear as bright as a star with a high luminosity present relatively far away.

Correct Answer: B