The root mean square velocity of the molecules in a sample of helium is `5//7th` that of the molecules in a sample of hydrogen. If the temperature of hydrogen sample is `0^(@)C`, then the temperature of the helium sample is about

Options

A. 278.46 K
B. `5.46^(@)C`
C. 273 K
D. a' and 'b'

Answer

D

Explanation

`V_("he")=(5)/(7)v_(h)`
`V_(2)=(5)/(7)V_(1)`
`sqrt((3RT_(2))/(M_(2)))=(5)/(2)xxsqrt((3RT_(1))/(M_(1)))`
`(T_(2))/(T_(1))=(25)/(4)xx(4)/(2)=(100)/(98)T_(2)`
`=1.02xx273=278.5K`