Physics - Heat & Thermo Question with Solution | TestHub

The intensity of solar radiation at a distance of $1.5\times 10^{11}$ m from the Sun is 1.4 kW $m^{-2}$. An iron dust particle melts at 1800 K. Treating the Sun and the particle as black bodies ($\sigma =5.67\times 10^{-8}$), find the distance from the Sun at which the particle starts melting, in units of $10^9$ m (two decimals).