(a) use the fact that the intergral of [z^3/((e^z)-1)] dz = (pi^4)/15 to show that the total radiant energy emitted per second by unit area of a blackbody is ((2pi^5)*(k^4)*(T^4))/15(c^2)(h^3)
(b) the sun's diameter is 1.4E9m and its effective surface temperature is 5800K. Assume the sun is blackbody and estimate the rate of energy loss by radiation from the sun
(c) use E=mc^2 to calculate the relativistic mass of photons lost by radiation from the sun in 1 year