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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 √2 times the speed of sound, then the value of n will be
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- 2
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Correct answer: 2
Solution
gamma_mix = (2*Cp_He + n*Cp_H2)/(2*Cv_He + n*Cv_H2) = (5+3.5n)/(3+2.5n) = 1.5. Solving gives 0.5 = 0.25n, so n = 2.
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