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# Is a slow process always isothermal? Is a quick process always adiabatic?

Answer :

An isothermal process is represented by the equation

PV = constant … (i),

where

P = pressure

V = volume.

To keep this product constant, a small change in V will only produce a small change in P and vice versa. Hence, an isothermal process is usually a slow process.

On the other hand, an adiabatic process is represented as

PV^{𝛾} = constant … (ii), where

P = pressure

V = volume

The 𝛾= ratio of specific heat capacities at constant pressure to constant volume.

Now, 𝛾 > 1. Hence, the term V^{𝛾} will increase exponentially. Hence, to keep the product constant, a small change in V will cause a large change in P. Hence, an adiabatic process is usually a fast process.

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