Two hydrogen atom collide Collide head on and end up with zero kinetic energy .Each atom then emit a photon of wavelength `121.6 nm` .Which transition leads to the wavelength ? How fast werte the hydrogen atom transition before collision ?

Explanation

Wavelength is emitted in UV regain and thus `n_(1) = 1`1 For H atom
`(1)/(lambda) = R_(H) [(1)/(1^(2)) - (1)/(n^(2))]`
`:. -(1)/(121.6 xx 10^(-6)) = 1.097 xx 10^(7)[(1)/(1^(2))- (1)/(n^(2))]`
`:.n = 2`
Also the energy released is due to collision and all the kinetic energy is released in the form of photon
`:.(1)/(2) mv^(2) = (hv)/(lambda)`
`(1)/(2) xx 1.67 xx 10^(-27) xx v^(2) = (6.625 xx 10^(-34) xx 3 xx 10^(8))/(121.6 xx 10^(-6))`
`: , v = 4.43 xx 10^(4) m s^(-1)`