If Cu H 2 O 4 2 + absorbs a light of wavelength 600   nm for d - d transition, then the value of…

If ${\left[\mathrm{Cu}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4\right]}^{2+}$ absorbs a light of wavelength $600 \mathrm{nm}$ for $\mathrm{d}-\mathrm{d}$ transition, then the value of octahedral crystal field splitting energy for ${\left[\mathrm{Cu}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ will be____$\times {10}^{-21} \mathrm{J}$ [Nearest integer]

(Given : $\mathrm{h}=6.63\times {10}^{-34}\mathrm{Js}$ and $\mathrm{c}=3.08\times {10}^8{ \mathrm{ms}}^{-1}$)