The atomic masses of He and Ne are 4 and 20 a.m.u. respectively. What is the ratio of de Broglie wavelength of Hegas at `-73^(@)C` compared to that of Ne gas at `727^(@)C` ?

Explanation

`m upsilon^(2)= 2"KE",upsilon=(( 2 "K.E.")/(m))^(1//2)`
` lambda=(h)/(m upsilon)=(h)/(m((2"K.E.")/(m))^(1//2))=(h)/((mxx2"KE")^(1//2))`
`(lambda_(He))/(lambda_(Ne))=sqrt((m_(Ne)xx"KE"_(Ne))/(m_(He)xx"KE"_(He)))=sqrt((m_(Ne)xxT_(Ne))/(m_(He)xxT_(He))) ` ( `:'KE propT`)
`m_(He)=4 u,m_(Ne)= 20 u , T_(He)=-73^(@)C " or " 200 K`,
`T_(Ne)= 727^(@)C " or " 1000 K`
` :. " "(lambda_(He))/(lambda_(Ne))=sqrt((20 xx 1000)/(4 xx 200)) sqrt(25)=5`
`lambda_(He)"is five times" lambda_(Ne)`.