The frequency of incident radiation is given as [f] = [tex]2*10^{14}[/tex] Hz
The energy of the photon will be calculated as -
E= hf
= [tex]6.63*10^-34\ J.S\ *[2*10^{14} \ Hz[/tex]
= [tex]13.26*10^{-20}\ J[/tex]
We have [tex]1.602*10^{-19}\ J[/tex] = 1 ev.
[tex]13.26*10^{-20}\ J=\frac{1}{1.602*10^{-19}} *13.26*10^{-20}\ ev[/tex]
[tex]=8.28*10^{-1}\ ev[/tex]
[tex]=0.828\ ev[/tex]
The photo electric emission is dependent on the work function of the metal.
If light of suitable frequency i.e the energy of incident radiation is greater than or equal to work function will incident on the metal surface, the electrons will be emitted from the surface barrier of the metal.
Hence, from the above calculated value, if the work function of a metal is less than 0.828ev, then electron emission will be possible.
Normally metals have a work function greater than 1 ev. So, for most of the metals, the electron will not be emitted. But for some alkali metals under suitable condition, the work function is less than 0.8 ev. The electron emission will be possible for these substances.
