The sun may be regarded as a black body at a temperature of \(5800 \mathrm{~K}\). Its diameter is about \(1.4 \times 10^{9} \mathrm{~m}\) while its distance from the earth is about \(1.5 \times 10^{11} \mathrm{~m}\).

(a) Calculate the total radiant intensity (in \(\mathrm{W} / \mathrm{m}^{2}\) ) of sunlight at the surface of the earth.

(b) What pressure would it exert on a perfectly absorbing surface placed normal to the rays of the sun?

(c) If a flat surface on a satellite, which faces the sun, were an ideal absorber and emitter, what equilibrium temperature would it ultimately attain?