The rate at which radiant energy from the sun reaches the earth's upper atmosphere is about 1.50 kW /m2• The distance from the earth to the sun is 1.50 X 1011 m, and the radius of the sun is 6.96 X 108 m.
(a) What is the rate of radiation of energy per unit area from the sun's surface?
(b) If the sun radiates as an ideal blackbody, what is the temperature of its surface?