ΔE=RH[1n21−1n22]
For 3 to 2 ΔE3→2=RH[122−132]
For 2 to 1 ΔE2→1=RH[112−122]
For 3 to 1 ΔE3→1=RH[112−132]
It is evident from Eqs. (i),(ii) and (iii), that ΔE3→1=ΔE3→2+ΔE2→1
(b) Also,E=hv; thus frequencies are also additive.
But E=hcλ and thus wavelength are not additive.