Assertion (A) : Under adiabatic conditions, a moist air parcel cools slowly and rises to greater height in atmosphere compared to a dry air parcel.
Reason (R) : Compared to dry air parcel, latent heat of condensation released within the moist air parcel reduces rate of cooling of the moist air parcel moving up under adiabatic conditions.
In the light of the above statements, choose the most appropriate answer from the options given below :
Assertion (A) states that under adiabatic conditions, a moist air parcel cools more slowly and rises to a greater height compared to a dry air parcel. This is accurate. As a moist air parcel rises, it expands and cools adiabatically. If it cools to its dew point, water vapor condenses.
The process of condensation releases latent heat. This released heat partially counteracts the adiabatic cooling, causing the moist parcel to cool at a slower rate than a dry parcel experiencing only adiabatic cooling.
Reason (R) explains that the latent heat of condensation released within a moist air parcel reduces its rate of cooling under adiabatic conditions, compared to dry air. This statement correctly identifies the physical mechanism.
The addition of heat from condensation makes the moist parcel warmer (or cooler at a reduced rate) than a dry parcel undergoing pure adiabatic expansion and cooling at the same altitude.
Because the moist air parcel cools more slowly due to latent heat release (Reason R), it maintains its buoyancy for longer. This allows it to ascend to a higher altitude before its density matches the surrounding air, validating Assertion (A).
Therefore, Reason (R) accurately explains why Assertion (A) is true.
Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct explanation of (A).
| List - I (Decomposition Processes) | List - II (Function) |
|---|---|
| A. Leaching | I. Degradation of humus by microbes to release inorganic nutrients |
| B. Catabolism | II. Accumulation of a colloidal dark coloured amorphous substance, which is a reservoir of nutrients |
| C. Humification | III. Bacterial and Fungal enzymes degrade detritus into simpler inorganic substances |
| D. Mineralization | IV. Water soluble inorganic nutrients go down into the soil and get precipitated |