A radiator in a domestic heating system operates at a surface temperat

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Homework Help Overview

The discussion revolves around a problem related to thermal radiation emitted by a radiator in a domestic heating system, specifically focusing on the application of the Stefan-Boltzmann Law to determine the rate of radiant heat emission per unit area for a black body at a given surface temperature.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning why the temperature is not raised to the fourth power in the calculations, with references to the Stefan-Boltzmann Law. There is also discussion about the correct application of the law and the significance of the Stefan-Boltzmann constant.

Discussion Status

The discussion is active, with participants exploring the reasoning behind the application of the Stefan-Boltzmann Law. Some guidance has been provided regarding the proportionality of radiation to the fourth power of absolute temperature, but there remains some confusion about the details and calculations involved.

Contextual Notes

There are indications of potential typographical errors in the original problem statement, particularly concerning the order of magnitude for the Stefan-Boltzmann constant. Participants are also navigating the implications of using absolute temperature in their calculations.

manal950
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A radiator in a domestic heating system operates at a surface temperature of 55 C.
Determine the rate at which it emits radiant heat per unit area if it behaves as a black body ?


741333203.jpg


why we did not square the temperature
I mean ( 273 + 55)^4

please I need your help
 
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manal950 said:
A radiator in a domestic heating system operates at a surface temperature of 55 C.
Determine the rate at which it emits radiant heat per unit area if it behaves as a black body ?


741333203.jpg


why we did not square the temperature
I mean ( 273 + 55)^4

please I need your help

Because radiation is proportional to the fourth power of the absolute temperature, not the square.

See the Stefan-Boltzmann Law:

http://en.wikipedia.org/wiki/Stefan–Boltzmann_law
 
my question why in the answer we did not say ( ( 273 + 55)^4 ) not ( 273 + 55) without power 4
 
Maybe same reason they did not put the right order of magnitude for the Stefan-Boltzmann constant (10^(-8) in SI units).
It may be simply some typo(s). The result seem to be OK. So they did take the fourth power to get that number.
 
It must to make temperature with power 4 ?
 
Yes.
 
ok and this value 5.6697 X 10^-8 for what ?
 
Stefan_Boltzmann constant. Did you even read about Stefan-Boltzmann law of radiation?
 

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