Find the typical de Broglie wavelength associated with a He atom in helium gas at room temperature `(27^(@)C)` and 1 atm pressure, and compare it with the mean separation between two atoms under these conditions.

Explanation

Use `lambda=(h)/(sqrt(3mkT)), m_(He)=(4xx10^(3))/(6xx10^(23))kg`
This gives `lambda=0.73xx10^(-10)m." Mean separation"`
`r=(V//N)^(1//3)=(kT//p)^(1//3)`
For `T=300K, p=1.01xx10^(5)Pa, r=3.4xx10^(-9)m`. We find `r gt gt lambda`.