Answer
$4.97\cdot 10^{-19}\text{J}$
Work Step by Step
$E_k=h\nu-h\nu_0=h\left(\frac{3\cdot 10^8\text{ms}^{-1}}{4\cdot 10^{-7}m}-4.38\cdot 10^{11}Hz\right)=6.63\cdot 10^{-34}\text{m}^2\text{kg}\text{s}^{-1}\cdot 0.7495\cdot 10^{15}Hz=4.97\cdot 10^{-19}J$
