- The wave nature of electrons has been utilized in the construction of electron microscope of high resolving power. This microscope is an important tool in research.
- Wave nature of electrons has been used in the study of thin surface films.
Wednesday, 28 September 2011
Application Of The Wave Nature Of Electron
Tuesday, 27 September 2011
Thomson And Reid's Experiment To Verify The Wave-Nature Of Electrons
In 1928, English physicists G.P. Thompson and A. Reid, working with high speed electrons, showed that when a narrow beam of high-speed electrons produced from heated tungsten filament was allowed to fall on the surface on of a thin metallic foil like Al Au, Pt etc. and the diffracted electrons are received on photographic plate kept in a short distance away, these electrons produce a different luminous spot composed of electronic bright and dark rings which are called electron beam diffraction rings or patterns.
These diffraction patterns are obtained due to the fact that metal consists of many microscopic crystals arranged in random fashion so that some are always at the proper angles to give reflection rings given by electron beam are found to be similar to those given by X-rays (which are waves) when they are diffracted by the same meta foil. This similarity between the electron beam diffraction rings and those of X-rays rings confirms that electrons are also waves.
These diffraction patterns are obtained due to the fact that metal consists of many microscopic crystals arranged in random fashion so that some are always at the proper angles to give reflection rings given by electron beam are found to be similar to those given by X-rays (which are waves) when they are diffracted by the same meta foil. This similarity between the electron beam diffraction rings and those of X-rays rings confirms that electrons are also waves.
(a) X-rays beam diffraction rings (b) Electron beam diffraction rings
Monday, 26 September 2011
Difference Between de Broglie's Matter Waves and Electromagnetic Wave
Main difference are given below:
- de Broglie's matter waves are not radiated into empty space or emitted by oscillating particles i.e. they are never dissociated from the particle but remain attached to the particle. On the other hand the electromagnetic waves (i.e. radiations) can be absorbed or emitted.
- de Broglie's matter waves travel with speeds which depend on the nature of the matter particles while electromagnetic waves proceed with the speed of light.
- de Broglie's matter waves are not electromagnetic in nature.
Sunday, 25 September 2011
Dual Nature of Matter or Electron: Wave-Particle Nature of Matter-de Broglie's Concept of Matter Wave
According to Max Planck s quantum theory of radiations some phenomenons like photoelectric effect and black body radiations can be explained, if light radiation is supposed to behave as a material particle which is localized at a particular point in space, while according to Maxwell's wave theory of radiation certain other phenomenons like diffraction, interference and polarization can be explained, if light radiation is supposed to behave as a wave which is spread out over space. Thus we find that light shows dual character, i.e. it behaves both as a material particle and as wave.
In 1924 a French physicist, Lonius de Brogile extended the idea of dual character of light to matter particles and suggested that all mater particles in motion (e.g. electrons, protons, neutrons, atoms or molecules etc) have a dual character, i.e. all matter particles posses characteristics of both a material particles and a wave. The wave associated with matter particles is called de Broglie's matter wave. The revulationary idea proposed by de Broglie that a material object posses both the particle and the wave properties known as the wave-particle duality in matter. The idea of wave-particle duality in matter led de Broglieto a very important conclusion that since an electron is also a kind of matter particle, it also, like matter particle, has a dual character i.e. an electron, like all other matter particles, bahave both as a material particle and as awave.
In 1924 a French physicist, Lonius de Brogile extended the idea of dual character of light to matter particles and suggested that all mater particles in motion (e.g. electrons, protons, neutrons, atoms or molecules etc) have a dual character, i.e. all matter particles posses characteristics of both a material particles and a wave. The wave associated with matter particles is called de Broglie's matter wave. The revulationary idea proposed by de Broglie that a material object posses both the particle and the wave properties known as the wave-particle duality in matter. The idea of wave-particle duality in matter led de Broglieto a very important conclusion that since an electron is also a kind of matter particle, it also, like matter particle, has a dual character i.e. an electron, like all other matter particles, bahave both as a material particle and as awave.
Sunday, 18 September 2011
Photoelectric Effect
What is Photoelectric Effect?
In some of their experiments Sir J.J Thomson and P.Lenard showed that when a beam of light of suitable wavelength or frequency is allowed to fall on the surface of a metal, the electrons are emitted (or ejected) from the surface of metal. This phenomenon of emission of electrons is known as photoelectric effect or photoelectric emission (photo means light). Although the electrons emitted from the surface are no different from all other electrons, it is customary to call these electrons as photoelectrons.
It may be noted that only a few metal can eject electrons when radiations from visible (which has less energy and hence is less energetic) fall on them, but many more metals are very much capable of ejecting electrons when a radiations from ultraviolet light (which has more energy and hence is more energetic) fall on them.
In some of their experiments Sir J.J Thomson and P.Lenard showed that when a beam of light of suitable wavelength or frequency is allowed to fall on the surface of a metal, the electrons are emitted (or ejected) from the surface of metal. This phenomenon of emission of electrons is known as photoelectric effect or photoelectric emission (photo means light). Although the electrons emitted from the surface are no different from all other electrons, it is customary to call these electrons as photoelectrons.
It may be noted that only a few metal can eject electrons when radiations from visible (which has less energy and hence is less energetic) fall on them, but many more metals are very much capable of ejecting electrons when a radiations from ultraviolet light (which has more energy and hence is more energetic) fall on them.
Spectrum
What Is Spectrum?
A spectrum is an array of waves or particles which is spread out according to the increasing or decreasing of some property such as wavelength or frequency.
Types of Spectrum
Depending on the nature of the source emitting the radiation, there are two types of spectra.
A spectrum is an array of waves or particles which is spread out according to the increasing or decreasing of some property such as wavelength or frequency.
Types of Spectrum
Depending on the nature of the source emitting the radiation, there are two types of spectra.
- Emission Spectra
- Absorption Spectra
- Continuous spectrum
- Discontinuous spectrum which may be a band spectrum or line spectrum. Line spectrum also called atomic spectrum.
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