What is the ratio of the velocity of sound in hydrogen ( γ = 5 7 ) to that in helium ( γ = 3 5 ) at the same temperature? (Molecular weight of hydrogen and helium is 2 and 4 respectively)

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What is the ratio of the velocity of sound in hydrogen ( γ = 5 7 ​ ) to that in helium ( γ = 3 5 ​ ) at the same temperature? (Molecular weight of hydrogen and helium is 2 and 4 respectively)

TestHub · Accepted Answer

Velocity of sound is given by V = M γ RT ​ ​ ∴ V He ​ V H ​ ​ = γ He ​ γ H ​ ​ ⋅ M H ​ M He ​ ​ ​ ( T is the same for both) = 5 7 ​ × 5 3 ​ × 2 4 ​ ​ = 5 42 ​ ​

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