begin mathsize 48px style Z subscript e f f end subscript equals Z minus space sigma space end style

Z = Effective nuclear charge; Z = Atomic Number ; σ = Shielding

begin mathsize 36px style 1 over lambda equals R Z squared open square brackets 1 over n subscript f squared minus 1 over n subscript i squared close square brackets end style

λ= Wavelength of the emmited light (electromagnetic rediation) in the vacuum ; R = Rydberg Constant (1.097x 107 m-1) ; Z = Number of proton in the nucleus of the element; nf = Principal quantum number of final state; ni = Principal quantum number of the initial state