$[Fe(CN)_{6}]^{4-}$ and $[Fe(H_{2}O)_{6}]^{2+}$ are of different colours in dilute solutions. Why?

(N/A) The colour of a coordination compound depends on the magnitude of the crystal-field splitting energy,$\Delta$.
This $CFSE$ depends on the nature of the ligand attached to the central metal ion.
In $[Fe(CN)_{6}]^{4-}$,$CN^{-}$ is a strong field ligand,which causes a large splitting of $d$-orbitals.
In $[Fe(H_{2}O)_{6}]^{2+}$,$H_{2}O$ is a weak field ligand,which causes a smaller splitting of $d$-orbitals.
Since the energy gap $\Delta$ is different for both complexes,the wavelength of light absorbed during the $d-d$ transition is different.
Consequently,the transmitted light (complementary colour) is also different,leading to different observed colours.