A little explanation of Photoelectric Effect ( in brief)

Before we go deep inside the details of Quantum Mechanics, firstly we have to understand the basic theories which are related to it and Photoelectric Theory is one such theory......Exited??? So, let's get started..........

By hearing the word ‘Photoelectric’ it seems quite interesting, isn’t it? Yeah, thats true its pretty interesting and the history of its is also amazing. We all know that Einstein got Nobel prize. But do you know for which theory he got the same? Its actually for the Photoelectric effect!!!

According to the Bohr’s model, its necessary to provide electrons with energy in the form of electromagnetic radiation in order for them to get to orbitals with higher energy. However, if an electron absorbs a wave of high frequency, sometimes this energy is sufficient to abandon the atom entirely. This phenomenon, when the electrons are released from the shell of atom is called the photoelectric effect.

It has been observed that there must be a minimum energy needed for electrons to escape from a particular metal surface and is called work function ‘W’ for that metal. The work function can be expressed in terms of frequency as,

W=hV_o…………..(1)

Where, h is the Planck’s constant and V_o is the threshold frequency (minimum frequency for photoelectric effect).

According to Einstein the Photoelectric effect should obey the equation,

hV=KE_max +W………….(2)

From the above expression,

KE_max=hV-hV_o

KE_max=h(V-V_o)…………..(3)

While Young’s experiment convincingly demonstrates the wave nature of light, the photoelectric effect sees light as a stream of particles. Therefore, electromagnetic radiation has both wave and particle nature.

Stoping Potential:-

Photoelectrons are emitted from a metal, when illuminated with light, above the threshold frequency of the metal, with a range of KE’s. The stopping potential is the voltage between the metal surface and a cathode, placed close to the surface, in a vacuum, which just stops them from producing a current. We can then assume that the max KE of the photoelectrons,

                                                             

KE(max) = eV(s)…….(4)

                    

where,V(s) is the stopping potential.

Einstein theorized that photons transfer an energy equal to E(p) = hf, and that the minimum energy required for a photon to penetrate the surface is a constant, called the ‘work function’ of the metal, W.

Cheers!!! See you Again......👍👍👍

Don't Forget to check our other posts too.........

Subscribe to the Blog and follow my social handles for latest updates........

You can directly talk with me on Instagram

To meet more physics Enthusiasts please join our Facebook Page 

Also for latest updates of my posts join me on Twitter

  

                                                                                                          -Ratnadeep Das Choudhury

                                                                                    Founder and Writer of The Dynamic Frequency