According to Stefan's law of radiation, a black body radiates energy `sigmaT^4` from its unit surface area every second where T is the surface temperature of the black body and `sigma = 5.67 xx 10^-8 W//m^2 K^4` is known as Stefan's constant. A nuclear weapon may be thought of as a ball of radius 0.5 m. When detonated, it reaches temperature of `10^6 K` and can be treated as a black body.
Estimate the power it radiates