What is the wavelength of light emitted when the electron of a hydrogen atom undergoes a transition from an energy level with `n= 4` to an energy level with `n = 2` ? What is the colour corresponding to this wavelength?

Answer

A, B, D

Explanation

`For n_(1) rarr n_(3)`
`(1)/(lambda) = R[(1)/(n_(2)^(2)) - (1)/(n_(1)^(2))]`
`(1)/(12818) = R[(1)/(9) - (1)/(25)]`
`R = (9 xx 25)/(16 xx 12818)Å`
`For n_(3) rarr n_(1)`
`(1)/(lambda) = R[1/1^(2) - (1)/(3^(2))] =(9 xx 25)/(16 xx 12818)xx (8)/(9)`
`:. lambda = 1025 Å`