The energy levels of a hypotherical one electron atom are shown in figure

Find the wave number of the photon emitted for the transition `n = 3 to n = 1`

Options

A. `2.23 xx 10^(7) m^(-1)`
B. `1.009 xx 10^(7) m^(-1)`
C. `3.005 xx 10^(6) m^(-1)`
D. `0.432 xx 10^(6) m^(-1)`

Answer

B

Explanation

`lambda = (12400)/(E_(3)^(Z) - E_(1)^(Z)) = (12400)/(12.52) 990 Å `
Wave number `= (1)/(lambda) = (1)/(990 xx 10^(-10) m) = 1.009 xx 10^(7) m^(-1)`