**Thermometric Property Definition:**

The property of an object which changes with temperature is called a **thermometric property. **The devices used to measure temperature are called **thermometers.**

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## Thermometric Property | Definition, Formulas, Properties – Thermometry and Calorimetry

Different **thermometric properties** and thermometers have been given below

- Thermometric property of constant volume gas thermometer.
- Electrical resistance Metals.
- Mercury column in Capillary Tube.

(i) **Pressure of a Gas at Constant Volume:**

\(\frac{p_{1}}{T_{1}}=\frac{p_{2}}{T_{2}}\) and p_{t} = p_{0} \(\left(1+\frac{t}{273}\right)\)

t = \(\left(\frac{p_{t}-p_{0}}{p_{100}-p_{0}} \times 100\right)^{\circ} \mathrm{C}\)

where, p_{0}, p_{100} and p_{t} are pressure of a gas at constant volume at 0°C, 100°C and t°C.

A constant-volume gas thermometer can measure temperature from – 200°C to 500°C.

(ii) **Electrical Resistance of Metals:**

R_{t} = R_{0} (1 + αt + βt²)

where, α and β are constants for a metal.

As β is too small therefore, we can take

R_{t} = R_{0} (1 + αt)

where,

α = temperature coefficient of resistance and

R_{0} and R_{t} are electrical resistances at 0°C and t°C.

α = \(\frac{R_{2}-R_{1}}{R_{1} t_{2}-R_{2} t_{1}}\)

where, R_{1} and R_{2} are electrical resistances at temperatures t_{1} and t_{2}.

or

t = \(\frac{R_{t}-R_{0}}{R_{100}-R_{0}}\) x 100°C

where, R_{100} is the resistance at 100°C.

Thermometric property of Platinum resistance thermometer can measure temperature from – 200°C to 1200°C.

(iii) **Length of Mercury Column in a Capillary Tube:**

l_{t} = l_{0} (1 + αt)

where

α = coefficient of linear expansion and

l_{0}, l_{t} are lengths of mercury column at 0°C and t°C.

**Thermometry and Calorimetry:**

The thermometer is a device used to check the temperature of an object. This branch of measurement of the temperature of a substance is called thermometry. It is measured in degrees or Fahrenheit, usually.

Calorimetry also means the measurement of heat but in joules. It states the amount of heat lost by the body is the amount of heat gained by its surrounding.