An athlete's body is cooled as sweat evaporates from the skin. During this process, the highest-energy water molecules escape into the air as water vapor.
Which of the following describes what happens to the average kinetic energy of the remaining water molecules and the temperature of the remaining sweat?
The average kinetic energy of the remaining molecules decreases, and the temperature of the remaining sweat decreases.
The average kinetic energy of the remaining molecules decreases, and the temperature of the remaining sweat increases.
The average kinetic energy of the remaining molecules remains the same, and the temperature of the remaining sweat decreases.
The average kinetic energy of the remaining molecules remains the same, and the temperature of the remaining sweat remains the same.
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.