State the phenomenon of photoelectric effect and explain the dependence of photocurrent and stopping potential on intensity and frequency.

The frequency of a beam of UV light is $1.0\times {10}^{15} \mathrm{Hz}$. What is the energy in one quantum of this light, express it in $eV$?

($\mathrm{e}=1.6\times {10}^{-19}\mathrm{C}, \mathrm{h}=6.63\times {10}^{-34}\mathrm{Js}$)

A certain spectral line has a wavelength of $4000 \stackrel{\mathrm{o}}{A}$. Calculate the frequency and energy of the photons associated with it.

$\left(\mathrm{e}=1.6\times {10}^{-19}\mathrm{C}, \mathrm{h}=6.63\times {10}^{-34}\mathrm{Js}\right)$

The energy of $6000 \stackrel{\mathrm{o}}{A}$ photon is $3.30\times {10}^{-19} \mathrm{J}$. Find the energy of $4000 \stackrel{\mathrm{o}}{A}$.

$\mathrm{e}=1.6\times {10}^{-19}\mathrm{C}, \mathrm{h}=6.63\times {10}^{-34}\mathrm{Js}$