CBSE-XI-Physics
27: Specific Heat Capacities of Gases
- #10The ratio Cp / Cv for a gas is 1.29. What is the degree of freedom of the molecules of this gas?Ans : For the molecules of a gas, `` \gamma =\frac{{C}_{\,\mathrm{\,p\,}}}{{C}_{\,\mathrm{\,v\,}}}=1+\frac{2}{f}``,
where f is the degree of freedom.
`` \,\mathrm{\,Given\,}:\gamma =1.29``
`` \Rightarrow 1+\frac{2}{f}=1.29=\frac{9}{7}``
`` \Rightarrow \frac{2}{f}=\frac{9}{7}-1``
`` \Rightarrow \frac{2}{f}=\frac{2}{7}``
`` \Rightarrow f=7``
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Therefore, the molecules of this gas have 7 degrees of freedom.
But in reality, no gas can have more than 6 degrees of freedom.
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