The Sun radiates like a perfect black body with an emissivity of exactly 1. 

(a) Calculate the surface temperature of the Sun, given that it is a sphere with a 7.00 × 10⁸-m radius that radiates 3.80 x 10²⁶ W into 3-K space. 

(b) How much power does the Sun radiate per square meter of its surface?

(c) How much power in watts per square meter is that value at the distance of Earth, 1.50 x 10¹¹ m away? (This number is called the solar constant.)