Strong ligand \(\alpha \)  \(CFSE\)   \(\alpha \) \({E_{absorbed}}\,\propto \,\frac{1}{{{\lambda _{absorbed}}}}\)

We have

\(\mathop {{{[CoCl{{(N{H_3})}_5}]}^{2 + }}}\limits_{(I)} ,\)  \(\mathop {{{[Co{{(N{H_3})}_5}{H_2}O]}^{3 + }}}\limits_{(II)} \)  and \(\mathop {{{[Co{{(N{H_3})}_6}]}^{3 + }}}\limits_{(III)} \)

\(\therefore \,III\, > \,II\, > \,I\)  (as per \({E_{absorbed}}\) )

\(\therefore \,\,\frac{1}{{{\lambda _{absorbed}}}}\)

\(I\, > \,II\, > \,III\)