What is the ratio of velocity of sound in hydrogen gas to that in air at NTP? (At NTP the density of hydrogen is `0.0009" gmcc"^(-1)` and that of air `0.001" gmcc"^(-1)`)

Options

A. `3/sqrt(10)`
B. `sqrt(90)`
C. `sqrt(10)/3`
D. `1/sqrt(90)`

Answer

C

Explanation

Given, density of hydrogen, `rho_(H)=0.0009" gmcc"^(-1)`
density of air, `rho_("air")=0.01" gm cc"^(-1)`
`v_(H)/v_("air")=sqrt(rho_("air")/rho_(H))=sqrt(0.001/0.0009)=sqrt(10/9)=sqrt(10)/3`