If a coordination complex M(CO)6 is colored due to d – d transition & its CFSE corresponds to that w — AITS & Test Series Chemistry Question

Question

If a coordination complex M(CO)6 is colored due to d – d transition & its CFSE corresponds to that wavelength which an electron emits on de – excitation from 4th orbit to 3rd orbit in Li2+ ion. Find the value of CFSE for the given complex. (take R∞ = 10^7 m^-1) Ch = 6.62 × 10^-34