Each square metre of sun’s surface radiates energy at the rate of 6.27×107 Wm−2. Assuming that Stefan’s law applies to the radiation, the temperature of sun’s surface is (Stefan’s constant σ=5.7×107 Wm−2K−4)
From Stefan’s law Q=σT4
∴ T=(Qσ)14=(6.27×1075.7×10−8)14=(1.1×1015)14K
Hence the correct choice is (d).