We are going to do the comparison of isothermal and adiabatic expansion by graphical method. But before that we need to know two things. For adiabatic process, for adiabatic process, you can draw a conclusion that is PV gamma is a constant. So, the product of P and B to the power gamma is a constant and it can be written as P proportional to 1 by V to the power gamma or you can simply say P is inversely proportional to V to the power gamma. Let us consider it to be equation number 1. Similarly, for isothermal process, for isothermal process, another conclusion can be drawn that is PV is equal to constant that is the product between the product of pressure and volume is constant in case of isothermal process and we can write P proportional 1 by V that is pressure is inversely proportional to the volume. So, these are the two cases for adiabatic and isothermal process. Now, let me draw a graph that is pressure volume graph for both of them. The pressure volume graph for isothermal and adiabatic process is like this. In Y axis, we need to consider pressure in X axis, we need to consider volume. So, this is the initial condition, this is initial condition. The pressure volume curve for isothermal process is like this that is as the volume increases the pressure decreases. But on the other hand, the pressure volume of the pressure volume curve for adiabatic process is like this that is it is more steeper than that one. This is for isothermal process, isothermal process and we know that for isothermal process, the change in internal energy is zero and the change in temperature is also zero and this is for adiabatic process. Adiabatic process and for adiabatic process, the change in heat energy will be zero that is there want to be any exchange of heat energy between the system and surrounding in case of adiabatic process. So, these are the two cards that we get if we plot pressure against volume for isothermal and adiabatic process. For isothermal process, the change in internal energy of the system will be zero. Similarly, the temperature change will also be zero. But in case of adiabatic process, temperature must change the temperature changes, but only the heat energy between the system and the surrounding is zero. We can see here the curve of adiabatic process is steeper than the curve of isothermal process. The reason for that is in isothermal process, there will be the exchange of heat energy between the system and surrounding. While expansion the gas needs some energy or heat energy that it gets from the surrounding surrounding will provide it, internal sorry surrounding will provide it, the heat energy that it needs for the expansion. But in case of adiabatic process, it cannot get the energy from outside. It has to use its whole internal energy in order to expand. Let us write this. Let me write over here in isothermal process. In isothermal process, the system gets heat energy, heat energy from surrounding to expand, to expand. But in case of adiabatic process, adiabatic process, the system can't get, can't get heat and has to use its own internal energy, internal energy in order to expand. And this is the reason why the adiabatic curve is steeper than the isothermal curve as well as also it is observed that the drop in pressure, the drop in pressure in case of adiabatic process, adiabatic process is greater than isothermal process, isothermal process for same volume of gas. That is you can see from graph over here, the drop in pressure for adiabatic process is obviously greater than in isothermal process, if we take the same volume of gas or same volume, the pressure change will be greater than in adiabatic process than in isothermal process. This is the graph that we get if we plot pressure against volume in these two process. And we know that the walk done simply is the area of pressure volume curve that is this area. This area is for isothermal process and this much area is for adiabatic process. This much area is for adiabatic process, then you can compare by yourself as well. The area of this whole region that is for isothermal process is greater than the area of adiabatic process. Then obviously the walk done in isothermal process is greater than that in adiabatic process. Hence the walk done in adiabatic process is less than that of isothermal process. Isothermal process. So by this graphical method we compared the walk done in adiabatic expansion and isothermal expansion that is isothermal expansion is requires more walk done.