# Heat change from a wire loop

1. Mar 25, 2015

### TheWire247

I am trying to calculate what the heat change from room temperature is in a wire loop is. I have the power P, the thermal conductivity K , the radius of the wire "a" and the radius of the loop "r". Using Fourier's Law:

$P = -KA \frac{\Delta T}{\Delta x}$

I am unsure what to use as A and $\Delta x$. I have the idea that A would be surface area of the wire ($4 \pi^{2} a r$) and $\Delta x$ would be the just a. Is my thinking right?

2. Mar 25, 2015

### T Damen

A is indeed the surface of the wire. Delta(x) is the distance between the end points. With the radius of the loop you should be able to get delta(x)!

3. Mar 25, 2015

### TheWire247

What do you mean by the end points. Is that the length of the wire?

4. Mar 25, 2015

### T Damen

Yes!

5. Mar 25, 2015

### Philip Wood

The set-up still isn't clear. 'Loop' implies no ends; between what points is there a temperature difference? Without a temperature difference no heat will flow.