Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the emitter is made.
In photoelectric effect an electromagnetic radiation (Can be Visible Light) is incident on a metal, if the energy of incident radiation is more than work function of the metal, then electrons are ejected out of the metal surface with some kinetic energy
Work function is the minimum Energy required to just pull out an electron from metal surface.
the setup for photoelectric effect has been shown in figure
Now the energy supplied to electron through photon (assuming light to be particle) is used up in overcoming the internal atomic forces to come to surface of metal (equal to work function of metal) and end extra energy is converted to kinetic energy of particle
So the maximum kinetic energy of an electron can be given by the photoelectric equation
Kmax = E – ϕo
Where Kmax is the maximum kinetic energy of electron.
E is the energy of incident radiation.
ϕo is the work function of metal.
We know energy of an electromagnetic radiation can be given by relation
E = h