Which of the following is NOT a factor that can increase the rate of evaporation of water in a lake?

Analyze the question: We need the option that does NOT increase the rate of evaporation of water.

Concept: Evaporation happens when molecules at the surface have enough kinetic energy to escape into the air. The rate depends on:

• Temperature: higher temperature gives molecules more energy.
• Average molecular speed / kinetic energy: faster molecules escape more easily.
• Surface area: a larger area lets more molecules escape.
• Humidity: drier air speeds up evaporation.
• Wind: it carries away vapour.
• Atmospheric pressure: higher pressure reduces evaporation, because it makes it harder for molecules to leave the surface. Lower pressure increases the rate.

Step-by-step check of each option:

• A. Increase in atmospheric pressure: this hinders escape of molecules, so it decreases the rate of evaporation. It is not a factor that increases it.
• B. Rise in temperature: increases the rate.
• C. Increase in average speed of molecules: more molecules can overcome the surface attraction, so the rate increases.
• D. Increase in kinetic energy of molecules: the same idea as C, so the rate increases.

Exam tip: Remember that evaporation is favoured by high temperature, large surface area, low humidity, wind, and LOW pressure. In "NOT a factor" questions, look for the option that works in the opposite direction. Options B, C, and D are all really the same idea (more molecular energy), so the odd one out is A.