Find the typical de Broglie wavelength associated with a He atom in helium gas at room temperature `(27 ""^(@)C)` and 1 atm pressure.

Explanation

Here, `T = 27^(@)C = 300K`,
P = 1 atm `= 1.01 xx 10^(5) N.m^(-2)`
Mass of He atom,
`m_(He) = (4)/("avogadro's number") = (4)/(6.023 xx 10^(23))`
`= 6.64 xx 10^(-27) kg`
`:.` Typical de Broglie wavelength
`lamda = (h)/(sqrt(3m_(He) kT))`
`= (6.626 xx 10^(-34))/((3 xx 6.64 xx 10^(-27) xx 1.38 xx 10^(-23) xx 300)^(1//2))m`
`= 0.73 Å`