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| Matter Waves |
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| The suggestion that matter may have wave like properties was first put forwarded in 1924-1925 by Louis De Broglie. He argued that if light, which consists of waves according to classical picture, can sometimes behave like particles, then it should be possible for matter, which consists of particles to exhibit wave-like character under suitable circumstances. He made the hypothesis that the relation between the energy E of a particle and the frequency 'u' of the associated wave is exactly the same as that between the energy of photon and the frequency of light radiation. |
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| This is called as dual nature of mater. The radiation has a dual aspect behaving either as waves or as particles (waves when it interferes, diffracts and particles in a photocell). Einstein showed that a particle having a finite mass has been supposed to be associated with a definite amount of energy given by his mass-energy relationship E = mc2. On this basis, a wave has a particle aspect. |
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| Einstein received the Nobel Prize in physics in the year 1921 for the quantum theory of photoelectric effect and not for the special theory of relativity. Not only in photoelectric effect, the particle like behavior of light was also seen in elastic scattering of photons with electrons. The scattering of monochromatic X-Rays from electrons was studied by Arthur Holly Compton. He observed that the scattered X-rays had longer wavelengths. The change in wavelength was found to be independent of the matter used for scattering but varies with the angle between the incident and the scattered rays. Compton could explain the effect observed by him by assigning momentum of magnitude hu/c to photons of energy hu. The elastic scattering of a photon from an electron at rest can be worked out by using the principles of conservation of energy and conservation of momentum. |
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| The discovery in 1905 of the dual nature of light was followed by the discovery of dual nature of matter. Even though there was no experimental evidence for the dual nature of matter. When postulated by De Broglie, experiments performed later on actually proved the duality of matter. We know that electrons are particles having a discrete mass and moving with a definite velocity. Sometimes these behave like waves and produce diffraction pattern as shown by Davison and Germer as also by Thomson. |
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Dual Nature of Radiation and Matter
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