Correct Answer - Option 3 : Isochoric
Explanation:
Work
- Work is said to be done by the system if the sole effect of the thing external to the system crosses the boundary.
- If there is no interaction of work between system and surrounding then work done is zero.
- Work is high-grade energy.
- It is also known as an organized form of energy.
Isochoric process:
- It is a thermodynamic process which takes place at constant volume.
- In such a process, the work done is zero. The volume of the gas remains constant.
For constant volume or Isochoric process work done is given by,
\(W = \smallint PdV\)
Since for isochoric process we know that,
dV = 0
so, W = 0 for Isochoric process.
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For free expansion work done is zero. i.e. W = 0
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The process in which high-pressure fluid is converted to low pressure by using a throttle valve is Throttling. In the throttling process enthalpy remains constant, hence work done is zero.
Adiabatic process:
- It is a thermodynamic process in which there is no exchange of heat from the system to its surrounding neither during expansion nor during compression, yet the temperature may change.
- For the adiabatic process to occur, the system must be perfectly insulated from the surrounding.
- A reversible adiabatic process is called isentropic.
For the adiabatic process, the work done by the system is given as
\(W = \frac{{{P_1}{V_1} - {P_2}{V_2}}}{{\gamma - 1}} = \frac{{nR\left( {{T_1} - {T_2}} \right)}}{{\gamma - 1}}\)
where R is gas constant, n is molar mass and \(\gamma = \frac{{{C_P}}}{{{C_V}}}\) , where Cp and Cv are specific heat at constant pressure and volume
Isothermal process
- It is a thermodynamic process in which the temperature of a system remains constant.
- The thermal equilibrium is maintained because the heat transfer is very slow.
- The work done in this process is due to the change of net heat content of the system.
For Isothermal process work done is given by,
\({W_{1 - 2}} = {p_1}{V_1}\ln \left( {\frac{{{p_1}}}{{{p_2}}}} \right) = {p_2}{V_2}\ln \left( {\frac{{{p_1}}}{{{p_2}}}} \right)\)
Isobaric process:
- It is a thermodynamic process in which the pressure remains constant.
For Isobaric process the work done is given by,
W = P ΔV
where P = pressure in N/m2, ΔV = Change in volume.