Question

The photoelectric work function for a metal surface is $3.84\times {10}^{-19}J$. If the light of wavelength $5000\mathring{A}$ is incident on the surface of the metal, will there be photoelectric emission?

Answer 1

Given that ;

Work function $\left(\varphi \right)=3.84\times {10}^{-19}J$

wavelength of incident light $=\lambda =5000\mathring{A}$

$\lambda =5000\mathring{A}=5000\times {10}^{-10}m=5\times {10}^{-7}m$

The Energy of the incident radiation is

$E=\frac{hc}{\lambda }$

$\Rightarrow \frac{6.62\times {10}^{-34}\times 3\times {10}^8}{5\times {10}^{-7}}$

$E=3.972\times {10}^{-19}J$

$\therefore E>\varphi$

As E is greater than $\varphi$. So, photoelectric emmission will occur.