General laws for expansion and compression:-
The general law of expansion or compression of a perfect gas is PVn = constant. It gives the relationship between pressure and volume of a given quantity of gas. The value of n depends upon the nature of gas and the condition under which the changes(i.e. Expansion or compression) takes place. The value of in may be between 0 and infinity. What the following values of n are important.
1) when n = 0, then pv0 = constant,i.e p = constant. In other words, for the expansion or compression of a perfect gas at constant pressure, n = 0.
2) when, n = 1, then pv = constant, i.e. The expansion or compression is isothermal for hyperbolic.
3) when n lies between 1 and n, the expansion or compression is polytropic, i.e pvn = constant.
4) when n = γ, function or compression is a adiabatic, i.e, pv γ = constant.
5) when n = infinity, the expansion or compression is at constant volume, i.e, v = constant.