Which of the following statements are true? (Select 4)
1. When air expands, its temperature will rise.
❌ False
In an adiabatic expansion, air does work on its surroundings, leading to a decrease in internal energy. Therefore, the temperature falls during expansion.
2. When air is compressed, its temperature will decrease.
❌ False
In an adiabatic compression, work is done on the air, increasing its internal energy and raising its temperature.
3. Heating happens through Compression of air parcel.
✅ True
When an air parcel is compressed, the temperature increases due to an increase in internal energy.
4. When air expands, its temperature will decrease.
✅ True
During adiabatic expansion, the air cools down as it does work on its environment.
5. Cooling happens through Expansion of air parcel.
✅ True
Expansion of an air parcel results in cooling due to reduced internal energy as work is done.
6. When air is compressed, its temperature will increase.
✅ True
Compression leads to a rise in temperature by increasing the internal energy of the air.
✅ Final Answer:
The four true statements are:
- 3. Heating happens through Compression of air parcel
- 4. When air expands, its temperature will decrease
- 5. Cooling happens through Expansion of air parcel
- 6. When air is compressed, its temperature will increase