Chapter 37 - The Foundations of Modern Physics - Exercises and Problems - Page 1121: 6

$P = 315~W$

We can find the temperature of the sphere: $\lambda = \frac{2.9\times 10^6~nm~K}{T}$ $T = \frac{2.9\times 10^6~nm~K}{\lambda}$ $T = \frac{2.9\times 10^{-3}~m~K}{2.0\times 10^{-6}~m}$ $T = 1450~K$ We can find the power emitted by the sphere: $P = e~\sigma~A~T^4$ $P = (1)~(5.67\times 10^{-8}~W~m^{-2}~K^{-4})(4\pi)(1.0\times 10^{-2}~m)^2~(1450~K)^4$ $P = 315~W$