Star E is the same temperature as star F, but star E is four times as luminous as star F. How do the radii of the stars compare?
A) Star E has twice the radius of star F.
B) Star E has four times the radius of star F.
C) Star F has twice the radius of star E.
D) Star F has four times the radius of star E.
E) They are the same size.

Question

Quizplus · Accepted Answer

The luminosity of a star is proportional to the square of its radius when temperature is constant. Since star E is four times as luminous as star F, its radius must be the square root of four times that of star F, which is twice the radius.

Star E Is the Same Temperature as Star F, but Star