An Isothermal Process is one that occurs at a constant temperature. During an isothermal process, the system exchanges heat with its surroundings in such a way that the temperature remains constant throughout. However, for an ideal gas undergoing an isothermal process, the relationship between pressure ($P$), volume ($V$), and temperature ($T$) is given by

Where:

• $P$ is the pressure of the gas,
• $V$ is the volume of the gas,
• $n$ is the number of moles of gas,
• $R$ is the ideal gas constant,
• $T$ is the temperature of the gas.