Thermodynamics - heat transfer

Click For Summary

Homework Help Overview

The discussion revolves around a thermodynamics problem concerning heat transfer, specifically focusing on how the radiated power of an object changes with temperature, given constant area and emissivity.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of the Stefan-Boltzmann law for calculating radiated power and explore the necessary temperature conversions from Celsius to Kelvin. There are attempts to compute the change in power using temperature values raised to the fourth power, and questions arise about how to find the ratio of the change in power to the original power.

Discussion Status

Some participants have provided equations and attempted calculations, while others are seeking clarification on how to proceed with finding the ratio of the change in power. The discussion reflects a mix of attempts and questions without a clear consensus on the next steps.

Contextual Notes

Participants note the importance of converting temperatures to Kelvin and the implications of maintaining constant area and emissivity in their calculations. There is a sense of urgency due to an impending exam, which may influence the depth of exploration in the discussion.

urgent
Messages
16
Reaction score
0

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!=]
 
Physics news on Phys.org
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
 

Similar threads

Replies
2
Views
264
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
992
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 6 ·
Replies
6
Views
1K
  • · Replies 4 ·
Replies
4
Views
4K