Which of the following relationships represents the change of entropy of a perfect gas?
1.\({C_v}\frac{{dT}}{T} + \frac{R}{V}dV\)
2.\({C_p}\frac{{dT}}{T} - \frac{R}{P}dP\)
3. \({C_v}\frac{{dP}}{P} + {C_p}\frac{{dV}}{V}\)
4. \({C_p}\frac{{dP}}{P} - {C_v}\frac{{dV}}{V}\;\)
1
1,2 and 4 only
2
1, 2 and 3 only
3
2,3 and 4 only
4
1,2,3 and 4