Energy of an electron is givem by `E = - 2.178 xx 10^-18 J ((Z^2)/(n^2))`. Wavelength of light required to excited an electron in an hydrogen atom from level `n = 1` to `n = 2` will be
`(h = 6.62 xx 10^-34 Js` and `c = 3.0 xx 10^8 ms^-1`).

Options

A. `1.325 xx 10^(-7)m`
B. `1.325 xx 10^(-10)m`
C. `2.650 xx 10^(-7) m`
D. `5.300 xx 10^(-10)m`

Answer

D

Explanation

`Delta E = - 2.0 xx 10^(-18) xx ((1)/(2^(2)) - (1)/(1^(2)))`
` = - 2.0 xx 10^(-18) xx (-3)/(4) , = 1.5 xx 10^(-18)`
`lambda = (hc)/(Delta E) = (6.6 xx 10^(-34) xx 3 xx 10^(8))/(1.5 xx 10^(-18)) = 1.325 xx 10^(-7) m`