- #1
Biker
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I took Stephan's law for thermal radiation and I have a couple of questions about it.
1) The law states that the full energy radiated in 1 sec is equal to c T^4 where c is 5.67*10^-8 and T in kelvins and In the book they said if it has surroundings then the net energy emitted would be
q = c A (T^4 -t^4) where t is the temperature of the surroundings. I don't understand how the energy received by the body would be c A t^4.
2) There was an example where a ball with some temperature T and it was connected to a metal cylinder fully covered from the sides by an insulator. When the book tried to calculate the amount of heat emitted by radiation, It subtracted the intersected area between the cylinder and the ball. But, Doesn't it also radiate? It should radiate with net energy. Energy from the radiation of the body minus energy radiated from the cylinder but How do you use stephan's law for non uniform temperature?
1) The law states that the full energy radiated in 1 sec is equal to c T^4 where c is 5.67*10^-8 and T in kelvins and In the book they said if it has surroundings then the net energy emitted would be
q = c A (T^4 -t^4) where t is the temperature of the surroundings. I don't understand how the energy received by the body would be c A t^4.
2) There was an example where a ball with some temperature T and it was connected to a metal cylinder fully covered from the sides by an insulator. When the book tried to calculate the amount of heat emitted by radiation, It subtracted the intersected area between the cylinder and the ball. But, Doesn't it also radiate? It should radiate with net energy. Energy from the radiation of the body minus energy radiated from the cylinder but How do you use stephan's law for non uniform temperature?