An athlete cools down after a race as sweat evaporates from their skin. Which molecules escape from the sweat and what happens to the average speed of the sweat molecules that remain on the skin?
the more energetic ones escape, and the average speed decreases
the more energetic ones escape, and the average speed increases
the less energetic ones escape, and the average speed decreases
the less energetic ones escape, and the average speed increases
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.