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For what kinetic energy of a neutron will the associated de Broglie wavelength be 1.40 × 10–10

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Also find the de Broglie wavelength of a neutron, in thermal equilibrium with matter, having an average kinetic energy of (3/2) k T at 300

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum

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What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root-meansquare speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Estimate the speed with which electrons emitted from a heated emitter of an evacuated tube impinge on the collector maintained at a potential difference of 500 V with respect to the emitter. Ignore the small initial speeds of the electrons. The specific charge of the electron, i.e., its e/m is given to be 1.76 × 1011 C kg–1 .(ii) Use the same formula you employ in (i) to obtain electron speed for an collector potential of 10 MV. Do you see what is wrong ? In what way is the formula to be

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) A monoenergetic electron beam with electron speed of 5.20 × 106 m s–1 is subject to a magnetic field of 1.30 × 10–4 T normal to the beam velocity. What is the radius of the circle traced by the beam, given e/m for electron equals 1.76 × 1011C kg–1 .(ii) Is the formula you employ in (i) valid for calculating radius of the path of a 20 MeV electron beam? If not, in what way is it modified? [Note: Exercises 20(ii) and 21(ii) take you to relativistic mechanics which is beyond the scope of this book. They have been

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An electron gun with its collector at a potential of 100 V fires out electrons in a spherical bulb containing hydrogen gas at low pressure (∼10–2 mm of Hg). A magnetic field of 2.83 × 10–4 T curves the path of the electrons in a circular orbit of radius 12.0 cm. (The path can be viewed because the gas ions in the path focus the beam by attracting electrons, and emitting light by electron capture; this method is known as the ‘fine beam tube’ method.) Determine e/m from the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An X-ray tube produces a continuous spectrum of radiation with its short wavelength end at 0.45 Å. What is the maximum energy of a photon in the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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From your answer to (i), guess what order of accelerating voltage (for electrons) is required in such a tube

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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In an accelerator experiment on high-energy collisions of electrons with positrons, a certain event is interpreted as annihilation of an electron-positron pair of total energy 10.2 BeV into two γ-rays of equal energy. What is the wavelength associated with each γ-ray? (1BeV = 109

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Estimating the following two numbers should be interesting. The first number will tell you why radio engineers do not need to worry much about photons! The second number tells you why our eye can never ‘count photons’, even in barely detectable light. The number of photons emitted per second

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Estimating the following two numbers should be interesting. The first number will tell you why radio engineers do not need to worry much about photons! The second number tells you why our eye can never ‘count photons’, even in barely detectable light. The number of photons entering the pupil

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Ultraviolet light of wavelength 2271 Å from a 100 W mercury source irradiates a photo-cell made of molybdenum metal. If the stopping potential is –1.3 V, estimate the work function of the metal. How would the photo-cell respond to a high intensity (∼105 W m–2) red light of wavelength 6328 Å produced by a He-Ne laser

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Monochromatic radiation of wavelength 640.2 nm (1nm = 10–9 m) from a neon lamp irradiates photosensitive material made of caesium on tungsten. The stopping voltage is measured to be 0.54 V. The source is replaced by an iron source and its 427.2 nm line irradiates the same photo-cell. Predict the new stopping

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A mercury lamp is a convenient source for studying frequency dependence of photoelectric emission, since it gives a number of spectral lines ranging from the UV to the red end of the visible spectrum. In our experiment with rubidium photo-cell, the following lines from a mercury source were used: λ1 = 3650 Å, λ2 = 4047 Å, λ3 = 4358 Å, λ4 = 5461 Å, λ5 = 6907 Å, The stopping voltages, respectively, were measured to be: `V_01` = 1.28 V,`V_02` = 0.95 V, `V_03` = 0.74 V, `V_04` = 0.16 V, `V_05` = 0 V Determine the value of

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The work function for the following metals is given: Na: 2.75 eV; K: 2.30 eV; Mo: 4.17 eV; Ni: 5.15 eV. Which of these metals will not give photoelectric emission for a radiation of wavelength 3300 Å from a He-Cd laser placed 1 m away from the photocell? What happens if the laser is brought nearer and placed 50 cm away

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Light of intensity 10–5 W m–2 falls on a sodium photo-cell of surface area 2 cm2 . Assuming that the top 5 layers of sodium absorb the incident energy, estimate time required for photoelectric emission in the wave-picture of radiation. The work function for the metal is given to be about 2 eV. What is the implication of your

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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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

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Obtain the de Broglie wavelength of a neutron of kinetic energy 150 eV. As you have seen in Exercise .31, an electron beam of this energy is suitable for crystal diffraction experiments. Would a neutron beam of the same energy be equally suitable? Explain. (mn = 1.675 × 10–27

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Obtain the de Broglie wavelength associated with thermal neutrons at room temperature (27 °C). Hence explain why a fast neutron beam needs to be thermalised with the environment before it can be used for neutron diffraction

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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