When a hydrogen atoms emits a photon of energy `12.1 eV` , its orbital angular momentum changes by (where h os Planck's constant)

Explanation

`E_(n_(2)) - E_(n_(1)) = 12.1 eV = 13.6 ((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))`
This equation is correct for transition from `n_(2) = 3 " to " n_(1) = 1`
Angular momentum `= (nh)/(2pi)`
`:.` Change in angular momentum `= (h)/(2pi) (n_(2) - n_(1)) = (h)/(2pi) (3 -1) = (h)/(pi) = (6.626 xx 10^(-34)Js)/(3.14)`
`= 2.11 xx 10^(-14) Js`