If $\left[\mathrm{Cu}\left(\mathrm{H}_2 \mathrm{O}\right)_4\right]^{2+}$ absorbs a light of wavelength 600 nm for d–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 $\mathrm{c}=3.08 \times 10^8 \mathrm{~ms}^{-1}$)