[" The earth receives on its surface radiation from "],[" the sun at the rate of "1400W/m^(2)." The distanced "],[" the centre of the sun from the surface of the earth "],[" is "1.5times10^(11)m" and the radius of the sun is "7.0x],[10^(8)m" .Treating sun as a black body,it follows "],[" from the above data that its surface temperature "],[" is "]