Question

If $\left[ Cu \left( H _{2} O \right)_{4}\right]^{2+}$ absorbs a light of wavelength $600 \,nm$ for $d - d$ transition, then the value of octahedral crystal field splitting energy for $\left[ Cu \left( H _{2} O \right)_{6}\right]^{2+}$ will be ______$\times 10^{-21}J$. (Nearest integer )
(Given : $h=6.63 \times 10^{-34} Js$ and $c =3.08 \times 10^{8} ms ^{-1}$ )

Answer 1

$\Delta_{ t }=\frac{ hc }{\lambda}=\frac{6.63 \times 10^{-34} \times 3.08 \times 10^{8}}{600 \times 10^{-9}}$
$=\frac{6.63 \times 3.08 \times 10^{-17}}{600}$
$=0.034034 \times 10^{-17}$
$=340.34 \times 10^{-21} J$
$\Delta_{0}=\frac{9}{4} \Delta_{ t }$
$=\frac{9}{4} \times 340.34 \times 10^{-21}$
$=765.765 \times 10^{-21} J$
$\approx 766 \times 10^{-21} J$