Author name: Manoj Pandey

Bohr combined classical and early quantum concepts and give his theory in the form of three postulates. (I) Bohr’s first postulate was that an electron in an atom could revolve in certain stable orbits without the emission of Radiant energy. According to this postulate, each atom has certain definite stable state in which it can exist […]

Rutherford’s model suffers to major drawbacks. 1. Stability of Atom: According to Maxwell, an accelerated charged particles emits radiation(energy). In Rutherford Model of atom, electrons are moving in circular orbits, Thus having centripetal acceleration. So electrons should emits radiation and ultimate lose energy and pulled into nucleus and atom would not be stable. So Rutherford

Distance of Closest Approach: As the Distance particle approaches the nucleus, the electrostatic force of repulsion due to nucleus increases and the kinetic energy of α particle goes on converting into the electrostatic potential energy. At a certain distance r₀ from the nucleus, whole of the kinetic energy of α particle convert into electrostatic potential energy

In this experiment H Geiger and E Marsden( Student of Rutherford and on suggestion of Rutherford) took ₈₃Bi²¹⁴ (Bismuth) as a source of α particles. A collimated beam of α particles of energy range (5 MeV to 7.7 MeV) was allowed to fall on 10⁻⁸ m to 10⁻⁶ m thick gold foil. The α particles

All elements consists of a very small invisible particles are called atoms. Atoms of some elements are same and atoms of different elements are different. #The first model of atom was proposed by JJ Thomson in 1898 called plum pudding model. According to this model, the positive charge of the atom is uniformly distributed throughout

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

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

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:-

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