Chapter 9, Problem 9.20E

Stefan’s law, equation $9.18$, suggests that any body of matter, regardless of the temperature, is emitting energy. At what temperature would a piece of matter have to be in order radiate energy at a flux of $1.00{\text{W/m}}^{\text{2}}$? At the flux of $10.00{\text{W/m}}^{\text{2}}$? $100.00{\text{W/m}}^{\text{2}}$?