Consider two ideal diatomic gases A and B at some temperature T. Molecules of the gas A are rigid, and have a mass m. Molecules of the gas B have an additional vibrational mode, and have a mass ${m \over 4}$ . The ratio of the specific heats ($C_V^A$ and $C_V^B$ ) of gas A and B, respectively is :
Solution
Degree of freedom of a diatomic molecule if
vibration is absent = 5
<br><br>Degree of freedom of a diatomic molecule if
vibration is present = 7
<br><br>$\therefore$ $C_V^A$ = ${5 \over 2}R$
<br><br>and $C_V^B$ = ${7 \over 2}R$
<br><br>$\therefore$ ${{C_V^A} \over {C_V^B}} = {5 \over 7}$
About this question
Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law
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