Name: Carnot Cycle : Third and Fourth Stage
Uploaded: 2019-07-19
Duration: 7 min 49 s
Description: Work is done on the system during the third and fourth stages of the Carnot cycle. The video teaches us how to calculate the total work done in a Carnot cycl...

Question

Distinguish between reversible and irreversible processes with examples. Discuss conditions for reversibility.

Accepted Answer

Reversible process $:$

Any process which can be made to proceed in the reverse direction by variation in its conditions such that any change occurring in any part of the direct process is exactly reversed in the corresponding part of the reverse process is called a reversible process.

If some work is done by the system in the direct process, an equal amount of work must be done on the system in the reverse process. If some heat is absorbed by the system in the direct process, it must release an equal amount of heat to the surroundings in the reverse process. At the end of the reversible process, both the system and surroundings must return to their initial state. Example $: ‐$

$(i)$ The process of gradual compression and extension of an elastic spring is approximately reversible.

$(ii)$ A working substance is taken along the complete Carnot's cycle.

Irreversible process $:$

Any process which cannot be retraced in the reverse direction exactly is called an irreversible process. Most of the processes occurring in nature are irreversible processes. Examples $: ‐$

$(i)$ Diffusion of gases.

$(ii)$ Dissolution of salt in water.

$(iii)$ Rusting of iron.

$(iv)$ Sudden expansion or contraction of the gas.

Necessary conditions for a reversible process are $:$

$1$ The process must be quasi-static. For this, the process must be carried out infinitesimally slowly so that the system remains in thermal and mechanical equilibrium with the surroundings throughout.

$2$ The dissipative forces such as viscosity, friction, inelasticity, etc. should be absent.

G L Mittal and TARUN MITTAL Solutions for Chapter: Carnot's Heat Engine : Second Law of Thermodynamics, Exercise 1: QUESTIONS

G L Mittal Physics Solutions for Exercise - G L Mittal and TARUN MITTAL Solutions for Chapter: Carnot's Heat Engine : Second Law of Thermodynamics, Exercise 1: QUESTIONS

Questions from G L Mittal and TARUN MITTAL Solutions for Chapter: Carnot's Heat Engine : Second Law of Thermodynamics, Exercise 1: QUESTIONS with Hints & Solutions

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