Thermodynamics Heat Radiation Problem

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SUMMARY

The discussion centers on solving a thermodynamics problem involving heat radiation from an automobile hood. The key equation used is Q/T = eθA(T1^4 - T2^4), where the emissivity (e) is 0.3, the Stefan-Boltzmann constant (θ) is 5.67 x 10^-8 W/m²-K⁴, the area (A) is 3.5 m², and the surrounding temperature (T2) is 20°C. The user seeks to determine the temperature (T1) of the hood, indicating a need for additional information regarding the power of sunlight to solve for Q/T effectively.

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  • Understanding of thermodynamics principles, specifically heat transfer.
  • Familiarity with the Stefan-Boltzmann Law and its application.
  • Knowledge of emissivity and its impact on thermal radiation.
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Students studying thermodynamics, engineers working on heat transfer problems, and anyone involved in automotive design or energy efficiency analysis.

astral87
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Hi everyone, I am unsure about how to solve this problem. I believe i have the right equation but I'm confused about how I can find Q/T with the information I am given. Is there another equation I can use?

Homework Statement



Assume the steel in the body of an automobile has an emissivity of 0.3 and a
specific heat of 450 J/Kg-degreeC. Take the area of the hood of the
automobile directly exposed to the sun as 3.5 square meters, and its mass
as 24.0 kg. What temperature will the top of the hood reach, assuming it
lost heat by radiating to its surrounding environment, which is at 20 degreesC?

Homework Equations



Q/T= eθA(T1^4-T2^4)
θ (Stefan-Boltzmann Constant) = 5.67 x 10^-8

The Attempt at a Solution



Q/T = (0.30)(5.67x10^-8 w/M2-K4)(3.5M2)[(T1^4-293.15^4 K)

I am searching for T1, anyone know how I can find Q/T? Maybe from another equation but I'm not sure which one.

Any help is appreciated, thank you!
 
Last edited:
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There seems to be missing info re the power of the sunlight.
 

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