The energy of an electron in excited hydrogen atom is -3.4 eV . Then, according to Bohr's therory, the angular momentum of the electron of the electron is

Options

A. `2.1xx10^(-34)J-s`
B. `3xx10^(-34)J-s`
C. `2xx10^(-34)J-s`
D. `0.5xx10^(-34)J-s`

Answer

A

Explanation

Energy of nth orbit in hydrogen spectra will be
`E=(-13.6)/(n^(2))`
`implies (-13.6)/(n^(2))=-3.4" "[given", "E_(2)=-3.4eV]`
`implies n^(2)=(-13.6)/(-3.4)=4simplies n=2`
So, angular momentum, `mvr=(nh)/(2pi)`
`implies =(2xx6.6xx10^(-34))/(2xx3.14)`
`=2.1xx10^(-34)J-s`