The angular momentum of electron in a Bohr's orbit of H atom is `4.2178 xx 10^(-34) kg m^(2)s^(-1)`. Calculate the wavelength of the spectral line when the electrton falls from this level to the next lower level.

Explanation

Given `"mur" = (nh)/(2pi)`
`:. (Nh)/(2pi) = 4.2178 xx 10^(-34)`
`or n = (4.2178 xx 10^(-34) xx 2 xx 3.14)/(6.626 xx 10^(-34)) = 4`
Thus `(1)/(lambda) = R_(H)[(1)/(n_(1)^(2)) - (1)/(n_(2)^(2))]`
The transition spectral line fourth shell is `(1)/(lambda) = 109678[(1)/(3^(2)) - (1)/(4^(2))]`
`:. lambda = 1.8 xx 10^(-4) cm`