Temperature & Thermometers — A/L Physics

What must I remember about Temperature & Thermometers?

• Concept of Temperature and Thermal Equilibrium: Zeroth Law of Thermodynamics: If bodies A and B are each in thermal equilibrium with a third body C, then A and B are in thermal equilibrium with each other (temperature is the property determining thermal equilibrium).
• Thermometric Properties: Any measurable physical property X that varies monotonically and continuously with temperature (e.g., volume of liquid in Mercury thermometer, resistance in Platinum resistance thermometer, pressure in constant-volume gas thermometer, thermoelectric emf in thermocouple).
• Linear Temperature Scale: Defined by two fixed points (Ice Point 0 °C, Steam Point 100 °C): θ = [(X_θ - X₀) / (X₁₀₀ - X₀)] * 100 °C.
• Thermodynamic Absolute Temperature Scale: Defined using Triple Point of Water (273.16 K): T = 273.16 * (P / P_tr) in constant-volume gas thermometer; completely independent of the properties of any working substance.

Test yourself (1 minute)

1. Thermometer Discrepancy

   Different types of thermometers calibrated at 0 °C and 100 °C generally disagree slightly at intermediate temperatures because thermometric properties do not vary strictly linearly with thermodynamic temperature.

2. Standard Thermometer

   The Constant-Volume Hydrogen Gas Thermometer is the internationally accepted standard against which other practical thermometers are calibrated.

3. Thermocouple Advantages

   Fast response time (very low thermal capacity), wide range (-200 °C to 1500 °C), can measure temperature at a pinpoint location.

Practise Temperature & Thermometers questions today

Source: NIE G.C.E. (A/L) Physics Resource Book - Unit 4: Thermal Physics

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What comes next?

Next in the syllabus

Where does Temperature & Thermometers fit in the syllabus?

Unit 4.1 · Grade 12 · Term 2