# To calculate the absolute magnitude of a star, what must be known in addition to the apparent magnitude?

To calculate the absolute magnitude of a star, what must be known in addition to the apparent magnitude?

Question 3 options:

radius

mass

distance

spectral type

Two stars of the same surface temperature are compared, and one is found to have a radius 1000 times larger than the other. How would their luminosities compare?

Question 5 options:

The larger one would have a luminosity 10 times larger than the smaller one.

The larger one would have a luminosity 100 times larger than the smaller one.

The larger one would have a luminosity 1000 times larger than the smaller one.

This is impossible, since the surface temperature of a star determines its radius.

The larger one would have a luminosity a million times larger than the smaller one.

In general, what can be said about type O and B stars compared to type K and M stars?

Question 6 options:

They are hotter and older.

They are cooler and older.

They are hotter and younger.

They are cooler and younger.

They are neither hotter nor cooler, younger nor older.