$\Rightarrow$ from Einstein equation : ${E}=\phi+{K} \cdot {E}_{\cdot \max }$

$\Rightarrow \frac{{hc}}{\lambda}={h} v_{0}+\frac{1}{2} {mv}^{2}$

$\Rightarrow \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{500 \times 10^{-9}}=6.63 \times 10^{-34} \times 4.3 \times 10^{14}+\frac{1}{2} {mv}^{2}$

$\Rightarrow \frac{6.63 \times 30 \times 10^{-20}}{5}=6.63 \times 4.3 \times 10^{-20}+\frac{1}{2} {mv}^{2}$

$\Rightarrow 11.271 \times 10^{-20} {~J}=\frac{1}{2} \times 9 \times 10^{-31} \times {v}^{2}$

$\Rightarrow {v}=5 \times 10^{5} \,{~m} / {sec}$