Heating time near a conductor

[elcraft]

Hi.

Practical situation.

If I have 0.25W of constant Joule loss around a small piece of copper electric conductor, then I would like to find out how much time until a small piece of "Something" (let's say 100mg at 1 kJ/kg*K) around the conductor heats up to 200°C.

From my calculations, the necessary heat will be Q = Specific heat of the Something (?) * mass of "Something" * (200°C - ambient temp).

So the amount of time to heat this up is supposed to be Q/0.25W. Am I right?

Or is there any other delay or heat loss that won't go into heating the "Something" to 200C? :shy:

 

[mfb]

If your system "conductor+something" is isolated from the environment and the heat capacity of the conductor is negligible, t=Q/0.25W. A real setup will heat the environment, too, and it will need longer to heat something.

 

[elcraft]

Heat capacity for the conductor (copper) is 0.385. I would like to take it into account, but how?

 

[mfb]

Just add the heat capacity (specific heat capacity * mass) to the other one. If the heating process is very quick, your conductor will have a higher temperature than the "something", and your estimate will be a bit off - you would need more data to account for that.

 

[sardar]

I can confirm that your calculations are correct. The amount of time it takes for the "Something" to heat up to 200°C will be Q/0.25W, assuming there are no other factors affecting the heating process. However, it is important to note that in a practical situation, there may be other variables at play that could affect the heating time, such as heat loss to the surrounding environment or the specific heat capacity of the "Something" being different from what was assumed. It is always best to conduct experiments or simulations to confirm the accuracy of your calculations.