Thermal Radiation Homework: Ranking Objects of Same Material

Click For Summary
SUMMARY

The discussion focuses on ranking three solid objects— a cube, a sphere, and a hemisphere—made of the same material and maintained at a temperature of 350K in an environment at 300K, based on their thermal radiation exchange rates. The key formula for this analysis is Stefan's Law, expressed as E=AσT^4, where E is the thermal radiation, A is the surface area, σ is the Stefan-Boltzmann constant, and T is the temperature. The objects should be ranked according to their surface areas, as this directly influences the rate of thermal radiation exchange. The correct order is determined by calculating the surface areas of each object and applying the formula to justify the ranking.

PREREQUISITES
  • Understanding of thermal radiation principles
  • Familiarity with Stefan's Law of black body radiation
  • Knowledge of surface area calculations for geometric shapes
  • Basic thermodynamics concepts
NEXT STEPS
  • Calculate the surface areas of the cube, sphere, and hemisphere
  • Apply Stefan's Law to determine the thermal radiation for each object
  • Explore the implications of temperature differences on thermal radiation
  • Research real-world applications of thermal radiation in engineering
USEFUL FOR

Students studying thermodynamics, physics enthusiasts, and anyone involved in materials science or engineering applications related to thermal radiation.

tjr39
Messages
12
Reaction score
0

Homework Statement



Consider the following three solid object all made of the same material;
1) Cube of edge length r
2) Sphere of radius r
3) Hemisphere of radius r

All object are maintained at a temperature 350K in an envorinment at temperature 300K. Rank the objects according to the net rate at which they exchange thermal radiation with the environment. Justify for full marks.

Homework Equations





The Attempt at a Solution



Im not sure whether to list them simply in order of surface area or not? Is there something else I should be considering? Cheers.
 
Physics news on Phys.org
tjr39 said:
Im not sure whether to list them simply in order of surface area or not? Is there something else I should be considering? Cheers.

So if you list them in terms of surface area, why would you justify it to be in that order?

Even though you have the correct idea, you should know this formula E=A \sigma T^4 (Stefan's law of black body radiation)
 

Similar threads

Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
7
Views
4K
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 5 ·
Replies
5
Views
520
Replies
3
Views
7K