Mechanical Engineering - Thermodynamics - Discussion

For a cyclic process, the system returns to its original state at the end of the process, so its entropy change is zero. But for the surroundings, that are typically envisioned as being comprised of ideal reservoirs, the entropy change is not necessarily zero. In the case of a reversible cycle, the change in entropy of the surroundings is zero. But, for an irreversible cycle, any entropy that is generated within the system during the cycle is transferred to the surroundings.

So, in this case, the entropy of the surroundings increases, but the entropy change of the system is still zero.

Disorder means here the randomness. The flexibility of the molecules to respond to the property changes and move their way randomly.

As per kinetic theory of gases, there is no particular force of attraction or repulsion existing between them and hence they can go randomly and respond randomly. This is said to be disorder.

Entropy is the disorder of anything.

For reversible cycle change in entropy is = 0.

For irreversible process change in entropy > 0.

If entropy < 0 then the process is impossible.

Nature always works in increasing entropy. Its linked to 2 nd law of thermodynamics as well.

Entropy is the property of a system which increases with addition of heat and decreases with removel of heat.

In irrevcesible process the system is not restore the intial position so we ading heat to do the work done so in irreversible its alwase increases.

Entropy is a property. Property is a point function. We know that change in the property of any cycle is zero. Means, the property of any cycle is constant if it's reversible or irreversible.

So, the correct answer is (A) remain constant.

Entropy is a system property. So cyclic integral of entropy is zero. Thus entrpoy of the system does not change.

But the entropy of the universe should obviously increase as it is irreversible process.

Low grade energy divided into two part available energy and unavailable energy. The unavailable energy is not use in the system. This UAE is called entropy and entropy is always increases.

Entropy of system depend on two factor 1st one is heat interaction. 2one is molecular disorder like friction due to intermolecular reaction.

In reversible system may increase or decrease.

In an irreversible process the entropy of the "system" may increase, decrease or remain constant but it always increases for the "universe" (increase in entropy principle).

Entropy for the irreversible system may remain greater than zero or may be less than zero. Entropy depends on internal irreversibility as well as external irreversibility.