Question

By what factor would a star's luminosity change if radius expands by a factor of 4?

Answer 1

If the radius of a star expands by a factor of 4, the luminosity would change by a factor of 256.

Step-by-step explanation:

Luminosity (L) is proportional to the fourth power of the radius (R), and the luminosity of a star is represented by L = M^3.9, where M is the star's mass.

If the radius of a star expands by a factor of 4, the luminosity would change by a factor of (4^4) = 256. This means the star would become 256 times brighter.

So, the luminosity of a star changes directly with the fourth power of its radius.