- #1
neelakash
- 511
- 1
The relation I= [tex]\sigma[/tex] [tex]\ T^4 [/tex] is exact for blackbodies and holds for all temperatures.Why is this relation not used as a basis of a definition of temperature at,say, 100*C?
(i)We do not deal with all black bodies around us.So, for specific objects,we are to put the value of emissivity which is unknown to us.
(ii) T will be a very slowly varying function of Intensity I.The temperature difference of two bodies will be very difficult to find if the total radiation is not tracked.This means,you have to keep track of all the wavelengths...
(iii)The calculation will be cumbersome...
(i)We do not deal with all black bodies around us.So, for specific objects,we are to put the value of emissivity which is unknown to us.
(ii) T will be a very slowly varying function of Intensity I.The temperature difference of two bodies will be very difficult to find if the total radiation is not tracked.This means,you have to keep track of all the wavelengths...
(iii)The calculation will be cumbersome...