Question

Consider a hydrogen atom. What wavelength of light (nm) will excite an electron from the n=4 to n=6 principal quantum level

Answer 1

Rydberg formula for hydrogen atom:

$1/\lambda = R_H(1/n_1^2-1/n_2^2)$,

where $\lambda$ is the wavelength needed, R_H is the Rydberg constant for hydrogen (1.09678*10⁷ m^-1), n₁ and n₂ are principal quantum numbers of the lower and higher energy levels respectively.

$1/\lambda = 1.09678*10^7(1/4^2-1/6^2)$

$\lambda$ = 2.626*10^-6 m = 2626 nm

Answer: 2626 nm