Energy of an electron is given 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. `1.214xx10^(-7)m`
B. `2.816xx10^(-7)m`
C. `6.500xx10^(-7)m`
D. `8.500xx10^(-7)m`

Answer

A

Explanation

`DeltaE=2.178xx10^(-18)(1/1^2-1/2^2)=(hc)/lamda`
`2.178 xx10^(-18)(1/1^2-1/2^2)=(6.62 xx10^(-34)xx3.0xx10^8)/(lamda)`
`:. lamda ~~ 1.214 xx10^(-7)m`