21Vn/Vhe = √1/7
ratio of the speed of sound in nitrogen to helium at 300 K is?
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14 Answers
1v = √(γ RT/M)
vN2/vHe = √((7/5)/(5/3)) * √4/28 = √21*4/25*28 =√3/25
1i saw plenty of answers above me . .but now i see only one brave man standing by his answer . .rest of the posts deleted !!
[50]
21he he....... No laplace was only crrct not newton!!
So ur ans is rite!!
21Hey, I was doubting myself [11]
Sir, can u pl. tell wer are v to use LAPLACE formula : Vsound = √γRT/M
coz i did it by : : Vsound = √RT/M [7]
11Wat is γ for helium and nitrogen?
The data for γ has to be given
11Therefore the speed ratio is
S = √(7*3/5*5
S = (√21)/5
S = 0.916
S = 0.92 is the raio of the speed of nitrogen to helium
1we should use laplace's equation only
it's speed of sound na .
v = \sqrt{\frac{\gamma RT}{M}}
we can't use newton's formula as it's experimentally found to be wrong and hence laplace's correction factor must be used
so we get
\frac{v_{N_{2}}}{v_{H_{2}}} = \sqrt{\frac{\gamma _{N_{2}}M_{H_{2}}}{\gamma _{H_{2}}M_{N}_{2}}}
so ans is
0.2449
39well, newton assumed it to be isothermal, and hence the formula he derived was way away from experimental results. laplace suggested travel of sound through gases is a adiabatic process as it occurs very rapidly and hence gave the formula ....(which srinath gave above).