Physics - Modern Physics Question with Solution | TestHub

$$\begin{array}{rl}& hv=W+\frac{1}{2}m{v}^2\text{ or }\frac{hc}{\lambda }=W+\frac{1}{2}m{v}^2\\ & \text{ Here }\lambda =3000\mathring{A}=3000\times 10^{-10}\mathrm{m}\\ & \text{ and }\mathrm{W}=1\mathrm{eV}=1.6\times 10^{-19}\text{ joule }\end{array}$$ $$\begin{array}{rl}& \therefore \frac{\left(6.6\times 10^{-34}\right)\left(3\times 10^8\right)}{3000\times 10^{-10}}\\ & =\left(1.6\times 10^{-19}\right)+\frac{1}{2}\times \left(9.1\times 10^{-31}\right){\mathrm{v}}^2\end{array}$$ Solving we get, $v\cong 10^6\mathrm{m}/\mathrm{s}$