Question

Write Einstein's equation of photoelectric effect. Give Einsteins explanation of photoelectric effect.

Answer 1

Einstein's equation of photoelectric effect is

$E_k=h\nu -\varphi =h\frac{c}{\lambda }-\varphi$

where $h=constant,c=\text{speed of light},\lambda =\text{wavelength of light,}\varphi =\text{work function of the metal}$

On the basis of the Einstein's equation,

• When ray of light is incident on the metal surface, then it absorbs this energy and emmits the electron from the surface of the metal.
• Some time electron is not ejected because incident energy is less than the work function of the metal.
• The maximum kinetic energy of the emerging electrons is independent of intensity of incident radiation but depends linearly on the frequency of the radiation,
  
• Electrons start emitting immediately after the light shines on surface without detectable time delay
  
• For a given frequency of incident radiation, above ${\nu }_o$, the number of electrons emitted per unit time is proportional to the intensity of incident radiation.