Thermodynamics - heat transfer

AI Thread Summary
The discussion focuses on calculating the increase in radiated power when the temperature of an object changes from 80 to 433 degrees Celsius, while keeping area and emissivity constant. The relevant equation used is P = φ*A*e*T^4, and participants emphasize the need to convert temperatures to Kelvin for accurate calculations. One user attempts to find the change in power by calculating the fourth power of the temperatures but struggles with determining the ratio of the change in power to the original power. The final steps involve calculating ΔE using the difference in the fourth powers of the temperatures and then finding the ratio ΔE/E. Understanding these calculations is crucial for exam preparation in thermodynamics.
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Homework Statement


if the temperature of an object changes from 80 to 433 degrees Celsius, but the area and emissivity remains constant, by how much does radiated power increase?


Homework Equations


P=phi*A*e*T^4


The Attempt at a Solution


i tried to do this:
80^4-433^4. and get the temperature change...but i do not know where to go from here, please if someone could give good explanation about this, i got an exam in 2 days=/..thanks!=]
 
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So the change is E=εA(T24-T14) (remember to change the temperatures to Kelvin).

Originally the power was E=εAT14

So what is the ratio of the change in power to the original power?
 
so i did this:
706^4 - 353^4
=2.329*10^11
um now how do i find the ratio of the change from this?
 
urgent said:
so i did this:
706^4 - 353^4
=2.329*10^11
um now how do i find the ratio of the change from this?

So you have ΔE= εA(2.239x1011)

Initially E = εAT14

So get E and just find ΔE/E
 
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