A student is calibrating a liquid-in-glass thermometer to establish a Celsius scale (∘C^\circ\text{C}∘C). Which row in the table correctly describes the conditions used to define the lower and upper fixed points?
| Lower fixed point | Upper fixed point | |
|---|---|---|
| A | Temperature of melting pure ice at 1 atm1\text{ atm}1 atm | Temperature of steam from pure boiling water at 1 atm1\text{ atm}1 atm |
| B | Freezing point of the thermometric liquid | Boiling point of the thermometric liquid |
| C | Temperature of melting pure ice at any pressure | Temperature of boiling pure water at any pressure |
| D | Temperature of freezing pure mercury at 1 atm1\text{ atm}1 atm | Temperature of steam from pure boiling water at 1 atm1\text{ atm}1 atm |
Row A
Row B
Row C
Row D
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.