A fixed mass `m` of a gas is subjected to transformation of state: `K` to L to `M` and black to `K` as shown in the figure.
The succeeding operations that enabel this transformation of state are

Options

A. cooling, heating, heating, cooling
B. cooling, heating, cooling, heating
C. heating, cooling, heating, cooling
D. heating, cooling, cooling, heating

Answer

D

Explanation

`K rarr L` : Process is isobaric. The volume of gas is increasing, thus, to keep the pressure constant, the system should be heated.
`L rarr M` : process is isobaric. The pressure of gas is decreasing which means the molecules are colliding with the walls with lesser force. This implies cooling.
`M rarr N`: process is isobaric. The volume of gas is decreaseing, thus, to keep the pressure constant, the system should be cooded to slow down the impact of molecules on the walls of the containers.
`N rarr K` : process is isochoric. The pressure of gas is increasing. This is possible by heating the system so that molecules collide with more vigor.
Alternatively, we can work out the answer using the ideal gas equation, `pV = nRT`