What is meant by the term thermometric property? (6) This graph was obtained during an experiment where the resistance R of a thermistor was measured as its temperature θ was raised from 0 °C to 100 °C (as measured by a mercury-in-glass thermometer) - Leaving Cert Physics - Question d - 2013

To find the temperature corresponding to a resistance of 420 kΩ, we can refer to the graph. By interpolation between the plotted points, we observe that the temperature of the water is approximately 61 °C.

Using the formula for emf under linear conditions:

heta = rac{100(EMF - E_0)}{E_{100} - E_0}

where:

• $E_0 = 0 \, \mu V$ at $0 °C$
• $E_{100} = 815 \, \mu V$ at $100 °C$
• $EMF = 319 \, \mu V$,

we can calculate:

$heta = \frac{100(319 - 0)}{815 - 0} = \frac{31900}{815} \approx 39.14 °C$

Thus, the temperature of the water in the tank as measured by the thermocouple thermometer is approximately 39.14 °C.

The thermistor and thermocouple thermometer exhibit different thermometric properties, meaning they respond differently to changes in temperature. Each device has its characteristic response curve, which can lead to discrepancies in the temperature readings under the same conditions.