You leave a black, spherical bowling ball out in the hot sun and it warms to a scalding hot temperature of 80ºC. The ball has a radius of 0.25 m (25 cm). What is the total power being radiated outward from this hot ball at this temperature?
Ans: Radiative power of the black spherical body , P = A x sigma x T^4 x epsilon
epsilon - emissivity of black body = 1
sigma - stefan boltzman constant = 5.67 x 10^-8 Wm^-2 K^-4
T - temperatureof the body = 80 degree C = 353.15 K
radius of the black body = 0.25 m
Surface area = 4 x pi x r^2 = 4 x 3.14 x 0.25^2 = 0.785 m^2
P = A x sigma x T^4 x epsilon
= 0.785 x 5.67 x 10^-8 x 353.15^4
= 692.3 W (Ans)
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