Integrated Concepts

(a) Calculate the rate in watts at which heat transfer through radiation occurs (almost entirely in the infrared) from 1.0 $\mathrm{m}^{2}$ of the Earth's surface at night. Assume the emissivity is $0.90,$

the temperature of the Earth is $15^{\circ} \mathrm{C},$ and that of outer space is 2.7 $\mathrm{K}$ (b) Compare the intensity of this radiation with that coming to the Earth from the Sun during the day, which averages about $800 \mathrm{W} / \mathrm{m}^{2},$ only half of which is absorbed. (c) What is the maximum magnetic field strength in the outgoing radiation, assuming it is a continuous wave?