Question

The speed of sound in oxygen (O₂) at a certain temprature is 460m/s . The speed of sound in helium (He) at the same temprature will be (assume both gases to be ideal ) [AIEEE 2008] ​

Answer 1

Explanation:- Speed of sound is given by

$V \: = \sqrt{ \frac{ \gamma \: R \: T}{M} }$

• For O₂ γ = 7/5 ,M = 32 [∵ diatomic gas]
• Vo₂ =√7/5RT/32

• for He γ = 5/3 [∵monoatomic gas]
• M =4
• Vₕₑ= √5/3RT/4

Vo₂ /Vₕₑ = 460× √5×32×5/7×3×4

Vₕₑ = 460×√5×32× 5/7×3×4 ≈ 420m/s Answer