Question

Explain the phenomenon of photoelectric emission.what are the law of Photoelectric effect? How are they explain by Einstein?

Answer 1

The Quantum Theory of Radiations by Max Planck can explain the photoelectric effect very well. Max Planck says that light is made of bundles of energy known as photons, energy of each photon being equal to hγ, γ being the frequency of the light. So when a photon of frequency being equal to the threshold frequency of the metal strikes the metal surface, it imparts its whole energy to an electron and hence helps the electron to overcome the forces of attraction from the nucleus of the atom. In this way, an electron is ejected out of a metal surface when a photon strikes it. If the frequency of the photon is less that γ0 (threshold frequency), then no photoelectric effect is observed.

But if γ>γ0, then some of its energy (which is equal to the ionization energy) is consumed in ejecting the electron from the metal and the remaining is used to impart some kinetic energy to the ejected electron.

Hγ= Ф + (½)mv2

Here, Ф is the ionization energy, v is the velocity imparted to the ejected electron, m is the mass of the electron.

As Ф=hγ0 , hγ= hγ0 + (½)mv2

Rearranging,  (½)mv2 = h (γ-γ0)………….(1)

Equation (1) is called Einstein photoelectric equation.

Answer 2

HEY MATE HERE IS YOUR ANSWER:-

PHOTOELECTRIC EMISSION:- The suitable frequency of light is required for emission if electron.

PHOTOELECTRIC EFFECT:
The phenomenon of ejection of electron from a metal surface, when light of suitable high frequency falls upon it is known as photoelectric effect . The electrons so emitted were called photo electron.

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