Balmer formula is an empirical formula to express the spectral wavelength of hydrogen atom, which was put forward by Swiss math teacher J J Balmer in 1885.

1/λ=r[ 1/(2^2)- 1/(n^2)]

r= 1. 1× 10⒎m^- 1

n=3，4，5……

λ=B*n^2/(n^2-4)

Mathematical law formula: (n+2)? ; /(n+2)？ ; -4

Where λ is the wavelength of the spectral line, and B=3.6546× 10-7m, which is a constant.