Vapour Pressure Of Liquid Solutions

Step 1: Understand the concept of humidity.

Humidity refers to the amount of water vapor present in the atmospheric air. It is a measure of how much moisture is in the air at a given time and location.

Step 2: Analyze the options.

• (1) Pressure difference in atmospheric air: Humidity is not related to pressure differences. This option is incorrect.
• (2) Amount of water vapour in atmospheric air: This is the correct definition of humidity.
• (3) Temperature in the atmosphere: Humidity is not directly related to temperature. This option is incorrect.
• (4) Quantity of heat energy given by the Sun: Humidity is unrelated to the Sun's heat energy. This option is incorrect.

Final Answer: Humidity refers to the , which corresponds to option .