(N/A) $1$. Isothermal Process: $A$ process in which the temperature of the system remains constant $(T = \text{constant})$. For an ideal gas, the internal energy remains constant $(dU = 0)$.
$2$. Adiabatic Process: $A$ process in which there is no exchange of heat between the system and its surroundings $(dQ = 0)$.
$3$. Isobaric Process: $A$ process in which the pressure of the system remains constant $(P = \text{constant})$.
$4$. First Law of Thermodynamics: For an ideal gas, the first law is given by $dQ = dU + dW$, where $dQ$ is the heat supplied to the system, $dU$ is the change in internal energy, and $dW$ is the work done by the system.