Question
During an adiabatic process of an ideal gas, if $$P$$ is proportional to $$\frac{1}{{\;{V^{1.5}}}},$$ then the ratio of specific heat capacities at constant pressure to that at constant volume for the gas is
A.
1.5
B.
0.25
C.
0.75
D.
0.4
Answer :
1.5
Solution :
$$\eqalign{
& {\text{As}}\,\,P \propto \frac{1}{{\;{V^{1.5}}}},\,{\text{So}}\,\,P{V^{1.5}} = {\text{constant}} \cr
& \therefore \gamma = 1.5\,\,\left( {\because {\text{Process}}\,{\text{is}}\,{\text{adiabatic}}} \right) \cr
& {\text{As}}\,{\text{we}}\,{\text{know,}}\,\,\frac{{{C_p}}}{{{C_v}}} = \gamma \cr
& \therefore \frac{{{C_p}}}{{{C_v}}} = 1.5 \cr} $$