Energy of an electron is given by, `E=-2.178 xx10^(-18) 4 ((Z^(2))/(n^(2))) J.` Wavelength of light required to excite an electron in hydrogen atom from level n = 1 to n = 2 will be: `(h = 6.62 xx 10^(-34) J s and c = 3 xx 10^(8) ms^(-1))`

Options

A. `6.500 xx 10^(-7) m`
B. `8.500xx10^(-7) m`
C. `1.214xx10^(-7) m`
D. `2.816xx10^(-7) m`

Answer

C

Explanation

`Delta E=(E_(2)-E_(1))`
`h (c )/(lamda) =((-2.178xx10^(-18))/(4))-((-2.178xx10^(-18))/(1))`
`(6.62xx10^(-34)xx3xx10^(8))/(lamda) =2.178xx10^(-18)[1-(1)/(4)]`
`lamda =(6.62xx10^(-34)xx3xx10^(8)xx4)/(3xx2.178xx10^(-18))=1.214xx10^(-7) m`