A liquid-in-glass thermometer is calibrated with a Celsius scale from −20∘C-20^\circ\text{C}−20∘C to 120∘C120^\circ\text{C}120∘C. Which points define the two standard fixed points used to calibrate this Celsius thermometer?
The lowest mark (−20∘C-20^\circ\text{C}−20∘C) and the highest mark (120∘C120^\circ\text{C}120∘C)
The temperature of melting pure ice (0∘C0^\circ\text{C}0∘C) and the temperature of steam from boiling pure water (100∘C100^\circ\text{C}100∘C) at standard atmospheric pressure
The beginning and end of the liquid column at the current temperature
The lower and upper ends of the glass tube containing the liquid
313 exam-style questions on CIE IGCSE Physics 2.2.3a Melting, boiling, condensation and solidification. Each one has a worked solution and a mark scheme showing where the marks go.