Mechanical Engineering - Thermodynamics - Discussion

For example, take an insulated piston cylinder device containing some arbitrary gas (common example in thermodynamics problems). If you were to push the piston down (thus compressing the contents of the cylinder), the temperature of the gas in the cylinder would increase. If the piston was pulled out (thus expanding the gas) the temperature would decrease. In either case, no heat would flow to or from the system, but the temperature would change approximately according to the relationship PV=nRT (for the most general cases).

So that's why this is the right answer.

There is no heat interaction between system and surrounding in adiabatic process.

Please apply concept of system and surrounding, the temp that is increasing is within the system and system is perfectly insulated. So there is no chances of heat interaction to surroundings.

That indicates dq = 0; So dw = -du.

Adiabatic process is the process where there is no change in internal energy of the system. Reversible adiabatic process is isentropic process means the amount of work is done is totally converted in heat.

Temperature of gas is not change.

Answer is D.

In adiabatic process no heat enters or leave. But in adiabatic compression & expansion the temp should be changes.

As no heat added then dw = 0.

dq = du+dw.
dq = 0, dw = 0.

So du = 0.
=>du = dw.

Adiabatic process there is no change of heat how temperature will change?

In adiabatic process n heat enters or leave, but if system works itself by spending its internal energy then definitely temperature will change, because system did some work but did not take heat from external sources. So it has to spend its internal energy if it is going to do some work.

An adiabatic as no heat added then dw = 0.

dq = du+dw.
dq = 0, dw = 0.

So du = 0.

=> du = dw process the work done is zero.

Due to change in internal energy, the temperature may change.

U = (KE + PE + IE).

KE is the kinetic energy of molecules = 3/2 kT (k = Boltzmann's const. & T = temperature).

PE is the potential energy.

IE is the intramolecular energy which may also lead to a change in temperature due to molecular re orientations.