The solar constant is the incident energy per unit of time on a unit area of a surface placed at right angles to a sunbeam just outside the earth's atmosphere.
The value of the solar constant is 1.37kW/m2. The area of a sphere with radius 93,000,000 miles is 2.79 X 1023m2, and the surface area of the sun is 6.09 x 1018 m2.
Assuming that the sun is a blackbody, calculate its surface temperature.