Question
What is the equation of state for isothermal process? Plot P versus V graph and P versus T graph for isothermal process for an ideal gas. Discuss the isothermal process using first law of thermodynamics.
Solution
An ideal gas equation is given by,
PV = nRT
In an isothermal process, temperature T is constant.
Therefore the equation of state for isothermal process reduces to,
PV = constant
The graph of P versus V and P versus T for an isothermal process is as shown below.
Now, according to first law of thermodynamics,

PV = nRT
In an isothermal process, temperature T is constant.
Therefore the equation of state for isothermal process reduces to,
PV = constant
The graph of P versus V and P versus T for an isothermal process is as shown below.

Now, according to first law of thermodynamics,
