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Question
Explain thermodynamics of the adiabatic process.
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Solution
- An adiabatic process is a process during which there is no transfer of heat from or to the system.
- For adiabatic change, Q = 0.
∴ ΔU + W = 0
∴ ΔU = –W - This implies, for adiabatic expansion, W is positive and ΔU is negative i.e. when work is done by the system adiabatically its internal energy decreases.
- Similarly, when a system is compressed adiabatically, W is negative and ΔU is positive i.e., the internal energy of the system increases in an adiabatic compression.
- Heat transfer to and from the system is prevented by either perfectly insulating the system from its environment or by carrying out the change rapidly so that there is no time for any exchange of heat.
- The temperature of the system changes, i.e., ΔT ≠ 0
- Usually, it is a sudden change and the system does not find any time to exchange heat with its environment.
- p-V diagram for the adiabatic process is as shown below:
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