Observed order of wavelengths, λabs =L3>L1>L2.
(Red light has highest wavelength of 700 nm while blue is the shortest with a wavelength of about 480 nm)
So, Δ0 (strength of ligands) order will be L2>L1>L3.
(As Δ0αλabs1 )
Hence, order will be L2>L1>L3.
Therefore, Strength of ligand ∝ΔAbsorption.