Thermodynamics HW Solutions 866

Thermodynamics HW Solutions 866 - Chapter 11 Fundamentals...

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Chapter 11 Fundamentals of Thermal Radiation 11-18 An isothermal cubical body is suspended in the air. The rate at which the cube emits radiation energy and the spectral blackbody emissive power are to be determined. Assumptions The body behaves as a black body. Analysis ( a ) The total blackbody emissive power is determined from Stefan-Boltzman Law to be 2 2 2 m 24 . 0 ) 2 . 0 ( 6 6 = = = a A s W 10 1.36 4 × = × = = ) m 24 . 0 ( K) 1000 )( K . W/m 10 67 . 5 ( ) ( 2 4 4 2 8 4 s b A T T E σ ( b ) The spectral blackbody emissive power at a wavelength of 4 is determined from Plank's distribution law, μ m T = 1000 K 20 cm 20 cm 20 cm μ m kW/m 10.3 2 = μ μ × μ μ × = λ λ = λ 1 K) m)(1000 4 ( K m 10 4387 . 1 exp m) 4 ( /m m W 10 743 . 3 1 exp 4 5 2 4 8 2 5 1 T C C E b 11-19E The sun is at an effective surface temperature of 10,372 R. The rate of infrared radiation energy emitted by the sun is to be determined. Assumptions The sun behaves as a black body.
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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