Question

The work function of a metal is $3.5\times {10}^{-19}eV$. If $5000A$ wavelength of light is incident on the metal, is there would be any photoelectric effect?

Answer 1

Given that,

Wave length $\lambda =5000\stackrel{\circ }{A}$

We know that,

The energy of a photon is:

${\varphi }^{}=\frac{hc}{\lambda }$

${\varphi }^{}=\frac{6.63\times {10}^{-34}\times 3\times {10}^8}{5000\times {10}^{-10}}$

${\varphi }^{}=3.98\times {10}^{-19}eV$

Hence, the enrgy of the icident photon is $3.98\times {10}^{-19}eV$ and is greater than the work function of the metal. Thus, there will be photo electric effect.