Thermodynamics question, heat transfer via radiation.

In summary, there is an experiment being described where an object with a surface area of 2 square meters is radiating energy at a rate of 1 kw per square meter. This energy is focused onto a second object with a surface area of 1 square meter using a system of mirrors and lenses. However, the temperature of the second object should not be higher than the first object, as they should eventually trend towards the same temperature. The difference in temperature between the objects determines the radiation rate and direction.
  • #1
mrspeedybob
869
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Suppose I have an object with a surface area of 2 square meters at a temperature which causes it to radiate energy at a rate of 1 kw per square meter. It has a very large thermal mass and so for the purposes of this experiment, a constant temperature . Around this object I have a system of mirrors and lenses which focus all of this energy onto a second object with a surface area of 1 square meter. The mirror and lens apparatus also works in reverse so that all radiation emited by the 1 square meter object ends up striking the 2 square meter object.

I have 2 kw of power striking my 1 square meter object, so it should assume a temperature at which it will radiate 2 kw of power, but that would mean it is radiating 2 kw per square meter which would make it hotter then the first object. That can't be right because they should trend toward the same temperature.

I feel like it should be obvious, but I can't see how the temperatures trend toward equal.
 
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  • #2
It is the temperature difference between the objects that determines the radiation rate/direction.
 

FAQ: Thermodynamics question, heat transfer via radiation.

1. What is thermodynamics?

Thermodynamics is the branch of physics that deals with the relationships between heat, energy, and work.

2. What is heat transfer via radiation?

Heat transfer via radiation is the process of transferring thermal energy through electromagnetic waves, without the need for a medium or direct contact between objects.

3. How does radiation differ from convection and conduction?

Radiation differs from convection and conduction in that it does not require a medium for heat transfer. Convection involves the transfer of heat through the movement of a fluid, while conduction is the transfer of heat through direct contact between objects.

4. What are some everyday examples of heat transfer via radiation?

Some examples of heat transfer via radiation in everyday life include feeling the warmth of the sun on your skin, cooking food in a microwave, and feeling the heat from a fireplace.

5. How does thermodynamics and heat transfer via radiation apply to real-world situations?

Thermodynamics and heat transfer via radiation have many applications in the real world, such as in the design of buildings and power plants, understanding climate change, and developing new technologies for renewable energy sources.

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