- #1
Karol
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Homework Statement
Two large plates are parallel and close to each other, vacuum is between them. they are held at 2000K and 3000K.
What is the energy transfer rate between them.
Homework Equations
The energy emission rate per unit area-the Stefan-Boltzmann Law: $$R=\varepsilon\sigma T^4$$
##\varepsilon## is the emissivity of the surface
##\sigma=5.672E-8[w/sec]##
The Attempt at a Solution
The solution is 368[w/m2], it's the answer if the emission is of a black body:
##1\cdot 5.672E-8\cdot\left(300^4-200^4\right)=368##
But why don't the emissivities of the surfaces count? what if one surface emits more or less than the other?
In the Stefan-Boltzman formula the outer temperature exists, not the nature of the surrounding surfaces.
I guess it has something to do with the fact that the rest of the radiation, which isn't absorbed, is reflected and comes into account