de Broglie (1924) predicted that small particles such as electrons should show wave -like properties along with paticle character. The wave length`(lamda)` associated with particle of mass m and moving with velocity v is given as `lamda=h/(mv)` where 'h' is plank's constant. The wave nature was confirmed by Davisson and Germer's experiment and modified equation for calculation of `lamda` can be given as:
`lamda=-h/(sqrt(2Em))` where E= kinetic energy of particle.
`lamda=h/(sqrt(2dVm))`, where d= change of particle accelerated potnetial of V volt.
The ratio of de-Broglie `chi` wavelength of molecules of `H_(2)` and He at `27^(@)C` adn `127^(@)C` respectively is

Options

A. 1.633
B. 0.612
C. 1.265
D. 0.79

Explanation

`lamda=h/(mv)`
`lamda_(H_(1))=h/(m_(H_(2))sqrt((3RT_(1))/(mH_(2))))`
`lamda_(H_(e))=h/(m_(H_(e))sqrt((3RT_(2))/(mH_(e))))`
`(lamda_(H_(2)))/(lamda_(H_(2)))=sqrt((T_(2)xxm_(H_(e)))/(T_(xxm_(H_(2))))`
`=sqrt((400xx4xx10^(-3))/(300xx2xx10^(-3)))`
`=sqrt(8/3)`
`=1.633`
Hence a is the correct option.