During a marathon, a runner's body is cooled as sweat evaporates from their skin.
Which of the following describes the molecules that escape from the liquid sweat during evaporation, and the change in the average speed of the remaining sweat molecules?
The more energetic molecules escape, and the average speed of the remaining molecules decreases.
The more energetic molecules escape, and the average speed of the remaining molecules increases.
The less energetic molecules escape, and the average speed of the remaining molecules decreases.
The less energetic molecules escape, and the average speed of the remaining molecules increases.
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.