Both neon `[ M_(Ne) = 20 xx 10^(-3) kg]` and helium `[M_(He) = 4 xx 10^(-3) kg]` are monoatomic gases and can be assumed to be ideal gases. The fundamental frequency of a tube (open at both ends ) of neon is `300 Hz at 270 K (R = ( 25//3) J//K mol)`
The fundamental frequency of the tube if the tube is filled with helium , all other factors remaining the same is

Options

A. `300 Hz`
B. `sqrt(2) xx 300 Hz`
C. `sqrt(3) xx 300 Hz`
D. `sqrt(5) xx 300 Hz`

Answer

D

Explanation

`M_(He) = 4 xx 10^(-3) kg`
`(n_(He))/(n_(Ne)) = sqrt((M_(n e))/(M_(He))) = sqrt((20)/(4))`
`n_(He) = sqrt(5) xx 300 Hz`