An ideal gas undergoes isothermal expansion (see the PV diagram). Entropy of the system is given by
1
\(\frac{\mathrm{P}_{1} \mathrm{~V}_{1}-\mathrm{P}_{2} \mathrm{~V}_{2}}{\mathrm{~T}} \)
2
\(\mathrm{nR} \ln \left(\frac{\mathrm{P}_{2}}{\mathrm{P}_{1}}\right) \)
3
\(\mathrm{nR} \ln \left(\frac{\mathrm{V}_{2}}{\mathrm{~V}_{1}}\right)\)
4
nRT (V2 - V1)