In thermodynamics for same change in volume, the work done is maximum in isobaric process because in P – V graph, area enclosed by curve and volume axis is maximum in isobaric process. ​

Gas expansion and work done

Gas expansion:
Gas expansion refers to the process in which a gas occupies a larger volume than before. This can occur due to various factors such as temperature changes, pressure changes, or changes in the number of gas particles.

Work done by the gas:
Work done by the gas during expansion is a measure of the energy transferred from the gas to its surroundings. It is given by the equation:

Work = Pressure * Change in Volume

The work done can be positive or negative depending on whether the gas is doing work on the surroundings (positive work) or work is done on the gas by the surroundings (negative work).

Types of expansion:
There are several types of gas expansions, including isothermal, adiabatic, and isobaric.

1. Isothermal expansion:
In an isothermal expansion, the temperature of the gas remains constant throughout the process. This can be achieved by placing the gas in thermal contact with a heat reservoir. During an isothermal expansion, the gas follows the ideal gas law, which states that the product of pressure and volume is constant:

P1 * V1 = P2 * V2

2. Adiabatic expansion:
In an adiabatic expansion, there is no exchange of heat between the gas and its surroundings. This can be achieved by insulating the gas or carrying out the expansion process very quickly. During an adiabatic expansion, the pressure and volume of the gas are related by the equation:

P1 * V1^gamma = P2 * V2^gamma

where gamma is the heat capacity ratio of the gas.

3. Isobaric expansion:
In an isobaric expansion, the pressure of the gas remains constant throughout the process. This can be achieved by allowing the gas to expand or contract against a constant external pressure. During an isobaric expansion, the work done by the gas is given by:

Work = Pressure * Change in Volume

Comparison of expansions:
When comparing the three types of expansions, it can be observed that the work done by the gas is greatest in an isobaric expansion. This is because in an isobaric expansion, the pressure remains constant, and the work done is directly proportional to the change in volume. In an isothermal or adiabatic expansion, the pressure and volume are related by different equations, which result in a smaller work done compared to an isobaric expansion.

Therefore, the correct answer is option 'C' - isobaric expansion.