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प्रश्न
Describe briefly how the Davisson-Germer experiment demonstrated the wave nature of electrons.
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उत्तर
Experiment:
Experimental arrangement used by Davisson and Germer: Electrons from a hot tungsten cathode are accelerated by a potential difference V between the cathode (C) and anode (A).
A narrow hole in the anode renders the electrons into a fine beam of electrons and allows them to strike a nickel crystal.
The electrons are scattered in all directions by the atoms in the crystal and its intensity in a given direction is found by the use of a detector.
The graph is plotted between angle Φ (angle between incident and the scattered direction of the electron beam) and intensity of the scattered beam.
The experimental curves obtained by Davisson and Germer are as shown in the figure below:
संबंधित प्रश्न
An electron and a photon each have a wavelength of 1.00 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electron.
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Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon).
Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage. Which probe has greater energy? (For quantitative comparison, take the wavelength of the probe equal to 1 Å, which is of the order of inter-atomic spacing in the lattice) (me = 9.11 × 10−31 kg).
The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relations:
E = hv, p = `"h"/lambda`
But while the value of λ is physically significant, the value of v (and therefore, the value of the phase speed vλ) has no physical significance. Why?
70 cal of heat is required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30°C to 35°C. The amount of heat required to raise the temperature of the gas through the same range at constant volume will be (assume R = 2 cal/mol-K).
An electron is moving with an initial velocity `v = v_0hati` and is in a magnetic field `B = B_0hatj`. Then it’s de Broglie wavelength ______.
A particle moves in a closed orbit around the origin, due to a force which is directed towards the origin. The de Broglie wavelength of the particle varies cyclically between two values λ1, λ2 with λ1 > λ2. Which of the following statement are true?
- The particle could be moving in a circular orbit with origin as centre.
- The particle could be moving in an elliptic orbit with origin as its focus.
- When the de Broglie wavelength is λ1, the particle is nearer the origin than when its value is λ2.
- When the de Broglie wavelength is λ2, the particle is nearer the origin than when its value is λ1.
A proton and an α-particle are accelerated, using the same potential difference. How are the de-Broglie wavelengths λp and λa related to each other?
Two particles A and B of de Broglie wavelengths λ1 and λ2 combine to form a particle C. The process conserves momentum. Find the de Broglie wavelength of the particle C. (The motion is one dimensional).
