Physics Question on Electric Current

Question

Sound travels in a mixture of two moles of helium and $n$ moles of hydrogen If rms speed of gas molecules in the mixture is $\sqrt{2}$ times the speed of sound, then the value of $n$ will be

Answer 1

Solution

vS=MγRT
vrms=M3RT
vrmsvs=3γ=21⇒3γ=21⇒γ=23
γ=1+fmix. 2
fmix. =n+22×3+n×5=(n+2)6+n×5
γ=1+6+n×52(n+2)=6+5n6+5n+2n+4
γ=6+5n7n+10=23
14n+20=18+15n
n=2