# Homework Help: I need you're help!

1. Oct 28, 2003

### robgb

Thermal physics question...

A wire resistance thermometer is constructed with material that has a resistance that varies as temperature as below.

R=R0 (1+ alphaT + betaT^2)
where constants alpha and beta are 3.8 x 10^-3 k^-1 and -3.0 x 10^-6 k^-2 respectively.

Calculate the temperature measured on the resistance scale at 70 degrees C on the ideal gas scale.

I've got no idea where to start on this one, any ideas?

Thanks, Rob.

Last edited: Oct 29, 2003
2. Oct 28, 2003

### mmwave

You must have the temperature at which the resistance thermometer has resistance R0 or you can't really do the problem. I suppose it could be absolute zero but that's not a very practical thermometer.

Also, the units for the constants don't make sense to me. Do you mean 10 * 103 or k for Kelvin?

Basically the resistance thermometer uses R at some given temperature and a formula for how the resistance varies with temperature. For example, at 0 C suppose R is 1000 ohms and the formula were
R0 + 10 T, then at 25 C, the resistance would be 1000 + 250 ohms.
Here T is relative to reference temperature 0 C.

3. Oct 29, 2003

### robgb

I've corrected the values of alpha and beta, does it make more sence now?

I've been told that this question has all the information you need to solve it.

Can anyone help?

Thanks, rob.