A quasi-static process has main characteristics as it is a

A quasi-static process has main characteristics as it is a

a. stationary process
b. infinitely slow process
c. random process
d. spontaneous process

Correct Answer : b. infinitely slow process

Explanation :

Consider a system of gas exists in a cylinder. The piston consists of many very small pieces of weights. Initially system is in an equilibrium state. When the gas system is isolated, the weights on piston are removed one by one slowly, at any instant of upward travel of the piston. So every state passes through by the system will be in an equilibrium state. Thus the system passes through the locus of all equilibrium points. This infinitely slow system is a quasi-static process. If the same small weights are now placed slowly one by one on top of the piston then the process will reverse in the same manner.