Question

What is adiabatic process

Answer 1

it a process which doesn't involve in transfer of energy from system to surrounding

Answer 2

In physics, an adiabatic process is a thermodynamic process  in which there is no heat transfer  into or out of a system and is generally obtained by surrounding the entire system with a strongly insulating material or by carrying out the process so quickly that there is no time for a significant heat transfer to take place.

Applying the first law of thermodynamics an adiabatic process, we obtain:

delta-U = -W

Since delta-U is the change in internal energy and W is the work done by the system, what we see the following possible outcomes. A system that expands under adiabatic conditions does positive work, so the internal energy  decreases, and a system that contracts under adiabatic conditions does negative work, so the internal energy increases.

The compression and expansion strokes in an internal-combustion engine are both approximately adiabatic processes—what little heat transfers outside of the system is negligible and virtually all of the energy change goes into moving the piston.