Can you please help me answer this astronomy question?

[FredB6025]

Use L=R^2*T^4 to calculate the radius of a 12,000 K (twice the temperature of the Sun), 0.0004-solar luminosity white dwarf.

[Trys]

Do your own homework!

[eri0397]

That's a pretty basic math question. Even Google will do it for you. T = 12,000 and R = 0.0004*the radius of the Sun (depending on the units of R). If you can't do it from there, you're really not prepared to take an astronomy class. Basic algebra.

[Brant2035]

0.0004 = r^2 (2^4)r^2 = 0.0004/16 = 0.000025r = 0.005 of the sun.Sun's radius = 695,000 Km. White dwarf is 0.005 x 695,000 = 3475 Km.