Isothermal process

 Isothermal process

When a system undergoes a process at constant temperature (△T =0), the process is called as an Isothermal process. or when there is change in the volume and pressure of a system without any change in temperature, the process is said to be isothermal. Boyle's law well describes an isothermal system. According to Boyle's law at constant temperature volume of a fixed mass of an ideal gas is inversely proportional to Pressure. During isothermal process, the heat is transferred at very slow rate such that change in temperature is negligible. thus Isothermal process is a slow process. Eg: melting of an ice.

Mathematical Expression for isothermal Process

let us consider a gas undergoing an isothermal process from initial state to final state.

From Ideal gas equation we can write

PV = constant

If P_i and V_i  and P_f and  V_f  are the pressure and Volume at initial and final state of the system, then  we can write 

   P_i V_i  =  P_f   V_f

Let work done in isothermal expansion of  gas from initial volume (V_i )to final volume(V_f) is given by

dW = PdV

The total workdone in expanding the gas is from initial volume (V_i )to final volume(V_f) is given by 

│<<<First law of thermodynamics││Isobaric Process>>>│

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