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. `1.214 xx 10^(-7)m`
B. `2.816 xx 10^(-7)m`
C. `6.5 xx 10^(-7)m`
D. `8.5 xx 10^(-7)m`

Answer

A

Explanation

`DeltaE = (hc)/(lambda) = 2.178 xx 10^(-18) ((1)/(n_(1)^(2))-(1)/(n_(2)^(2)))`
`(6.6256 xx 10^(-34) xx 3 xx 10^(8))/(lambda) = 2.178 xx 10^(-18) ((1)/(1^(2))-(1)/(2^(2)))`