Based on the equation :
`Delta E=-2.0xx10^(-18)J ((1)/(n_(2)^(2))-(1)/(n_(1)^(2)))`
the wavelength of the light that must be absorbed to excite hydrogen electron from level n = 1 to level n = 2 will be `(h=6.625xx10^(-34) Js, C=3xx10^(8) ms^(-1))`

Options

A. `1.325xx10^(-7)m`
B. `1.325xx10^(-10)m`
C. `2.650xx10^(-7) m`
D. `5.300xx10^(-10) m`

Answer

A

Explanation

`Delta E= - 2.0xx10^(-18)xx((1)/(2^(2))-(1)/(1^(2)))`
`= -2.0xx10^(-18)xx(-3)/(4)`
`=1.5xx10^(-18)`
`Delta E=(hc)/(lamda)`
`lamda=(hc)/(Delta E)=(6.6xx10^(-34)xx3xx10^(8))/(1.5xx10^(-18))=1.325xx10^(-7)m`