# Ncert 12th Physics Chapter-11

## Davission and Germer Experiment

The de-Broglie suggested that every moving particle has a wave associated with it. Davission and Germer experimentally proved that fast moving electron(particle) show diffraction, which is a property of of wave. Experimental Setup and Construction: It consists of an electron gun which compares of a tungsten filament F, coated with barium oxide and heated by […]

## De-Broglie Wavelength of an Electron

Let an electron of charge e having mass m be accelerated from rest through a potential difference V, then

## Dual Nature of Radiation

Wave theory of electromagnetic radiations explained the phenomenon of interference, diffraction and polarization of light. On the other hand, Quantum theory of electromagnetic radiations successfully explained the photoelectric effect, Compton effect, black body radiation e.t.c. It means that radiation sometimes behaves as a wave and sometimes as a particle. Wave Nature of Matter(Particles): De-Broglie Hypothesis:-

## Particle Nature of Light

Photoelectric effect gave evidence that light consists of packets of energy. These packet of energy is called light Quantum that are associated with particles named as photons. So photons confirm particle nature of light. Characteristic Properties of Photons: The following characteristic of photon which proves particle nature of light. (I) In the interaction of radiation

## Einstein’s Photoelectric Equation

According to Planck’s Quantum theory, light radiations consists of tiny packets of energy called quanta. One quantity of light radiation is called a photon which travels with the speed of light. The energy of a Photon is  E= hv Where h is Planck’s Constant and v is frequency of light radiation. When a photon of energy fall

## Law of Photoelectric Emission

The laws of photoelectric emission are as follows (I) For a given material and a given frequency of incident radiation, the photoelectric current or number of photoelectrons ejected per second is directly proportional to the intensity of the incident light. (II) For a given material and frequency of incident radiation, situation current is found to

## Photoelectric Effect and Experimental Study

Photoelectric Effect: It is the phenomenon of emission of electrons from the surface of metal, when radiations of suitable frequency fall on it. Or The phenomenon of converting light energy into electrical energy is called Photoelectric effect. The emitted electrons are called photoelectrons and the current, so produced is called photoelectric current. Threshold Frequency: For

## Electron Emission and Work Function

Electron Emission: In metals the electrons in the outer shells are loosely bound to the atoms, hence they are free to move easily the metal surface but I cannot leave the metal surface. Such electrons are called free electrons. These free electrons can be emitted from the metals, if they have sufficient energy to overcome

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