A metal ball of surface area $200\ cm^{2}$ and temperature $527℃$ is surrounded by a vessel at $27℃$. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is $(\sigma = 5.67 imes 10^{- 8}J/m^{2} - s - K^{4})$

Question

A metal ball of surface area $200\ cm^{2}$ and temperature $527℃$ is surrounded by a vessel at $27℃$. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is $(\sigma = 5.67 	imes 10^{- 8}J/m^{2} - s - K^{4})$

Dr. Abubacker · Accepted Answer

(c) Rate of heat loss $E = \sigma\ eA(T^{4} - T_{0}^{4})$
$5.67 	imes 10^{- 8} 	imes 0.4 	imes 200 	imes 10^{- 4} 	imes \lbrack(273 + 527)^{4} - (273 + 27)^{4}brack$
$5.67 	imes 10^{- 8} 	imes 0.4 	imes 200 	imes 10^{- 4} 	imes (800)^{4} - (300)^{4} = 182\ J/s$

Q. A metal ball of surface area $200\ cm^{2}$ and temperature $527℃$ is surrounded by a vessel at $27℃$. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is $(\sigma = 5.67 \times 10^{- 8}J/m^{2} - s - K^{4})$

Explanation

Reviewed by Dr. Abubacker

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