The correct option is 1, 2, 3 and 4.
Explanation
Condensation is the transformation of water vapour into liquid water. This process occurs when the air reaches a state of saturation, meaning it can no longer hold the water vapour present within it.
Condensation is influenced by the interplay of the following factors:
- Temperature: The moisture-holding capacity of air is directly proportional to its temperature. When air is cooled to its dew point, it becomes saturated, and any excess water vapour condenses into liquid form.
- Humidity: The absolute amount of water vapour present in the air is critical. Higher humidity means the air is closer to its saturation point, requiring less cooling for condensation to occur.
- Pressure and Volume: These factors are linked through adiabatic processes. When air rises, atmospheric pressure decreases, causing the volume of the air parcel to increase (expansion). This expansion leads to a decrease in temperature (adiabatic cooling), which is the primary mechanism for cloud formation. Conversely, compression increases pressure and temperature, inhibiting condensation.
Therefore, condensation generally takes place under three conditions:
- When the temperature of the air is reduced to the dew point with its volume remaining constant.
- When both the volume and the temperature are reduced.
- When moisture is added to the air through evaporation.
Key Takeaway: Condensation is driven by the cooling of air (temperature), the availability of moisture (humidity), and physical changes in the air parcel governed by pressure and volume (adiabatic changes).