Platinum Resistor: Measuring Temperature with High Accuracy

[ilyas415]

Homework Statement

A Pt-resistance thermometer is used to measure temperatures in the range 0°C to 100°C. The electrical resistance of the thermometer is 2 Ω at 20°C and 6 Ω at 100°C. It is necessary to measure the temperature to an accuracy of ± 0.1 K. How accurately must the electrical resistance be measured?

Homework Equations

I don't think you need any equations.

The Attempt at a Solution

I tried assuming a linear relationship because the liquid in the thermometer must have a linear expansion. I figured out the linear relationship:

T = 20R - 20 [where T is the temperature in celsius and R is the resistance in ohms].

However, after this, I'm not sure how to approach the question. I don't quite fully understand what the question is asking. Any help will be appreciated. Thanks in advance.

 

[lewando]

The question is asking you to perform some kind of error analysis based on accuracy of the measured resistance--if R is off by so much, how far off will T be, etc. But you should also pay attention to the original data that you used to form your equation. What kind of uncertainties are associated with those data?

 

[tiny-tim]

hi ilyas415!

The electrical resistance of the thermometer is 2 Ω at 20°C and 6 Ω at 100°C. It is necessary to measure the temperature to an accuracy of ± 0.1 K. How accurately must the electrical resistance be measured?
…
However, after this, I'm not sure how to approach the question. I don't quite fully understand what the question is asking.

how much difference in R corresponds to a difference of 0.1 K in T ?