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Adiabatic processes are thermodynamic processes in which no heat is exchanged between the system and its surroundings. This means that the heat transfer (Q) is zero (Q = 0). Adiabatic processes are often idealized in theoretical analysis, but they can be approximated in real-world situations, such as in the compression and expansion of gases in a piston-cylinder arrangement with well-insulated walls.

In an adiabatic process, the work done by or on the system is equal to the change in the internal energy of the system. This is expressed by the first law of thermodynamics, which states that the change in internal energy (ΔU) is equal to the heat added to the system minus the work done by the system (ΔU = Q - W). Since Q is zero in an adiabatic process, the equation simplifies to ΔU = -W.

Adiabatic processes can be further classified as adiabatic compression and adiabatic expansion. In adiabatic compression, the system does work on its surroundings, causing an increase in its internal energy. Conversely, in adiabatic expansion, the system's internal energy decreases as it does work on its surroundings.

The adiabatic process is also associated with the concept of entropy, a measure of the disorder or randomness in a system. In an adiabatic process, the entropy of the system remains constant because no heat is exchanged with the surroundings. This is known as an isentropic process.

Adiabatic processes are fundamental in various fields, including engineering, physics, and meteorology. For example, in engineering, adiabatic processes are used in the design of turbines and compressors. In meteorology, adiabatic processes play a crucial role in understanding weather patterns and atmospheric phenomena.