It was Robert Millikan who tested the Einstein photoelectric equation. He first calculated the kinetic energy gained by the emitted electrons for a number of frequencies by applying an opposing potential and finding the value at which the photoelectric current stops. Knowing the values of ...

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 ...

This is an effect observed by Sir J.J Thompson while performing some of his famous experiments. He observed that electrons are ejected by a metal surface when light of a certain frequency strikes the surface of a metal. This phenomenon observed is known as photoelectric ...

The distribution of energy in the spectrum of radiations of a hot body cannot be explained by applying the classical concepts of physics. Max Planck gave an explanation to this observation by his Quantum Theory of Radiation. His theory says: - a)      The Radiant energy is ...

What is a black body? A body which absorbs all the radiations falling at its surface is called a black body. A black body is also a perfect emitter .i.e. emits maximum energy out of all the bodies at same temperature. Whenever a body gets hot, it ...

Atomic Number The total number of unit positive charges present in the nucleus of an atom is known as its Atomic Number which is equal to the number of protons in the nucleus of an atom. Atomic Number for any two different atoms is never same ...

Chadwick performed the same experiment of Rutherford but with beryllium/boron sheet few years after Rutherford’s. He found that new particles carrying no charge and mass almost equal to proton were emitted. This neutral particle is known as neutron. Rutherford suggested an atomic model based upon his ...

Ernest Rutherford performed an experiment in 1911 to know more about the structure of atom. He made a narrow beam of α particles (obtained from polonium) to strike an extremely thin sheet of metal such as gold and silver. A fluorescent sheet was placed behind ...