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An electron microscope uses electrons accelerated by a voltage of 50 kV. Determine the de Broglie wavelength associated with the electrons. If other factors (such as numerical aperture, etc.) are taken to be roughly the same, how does the resolving power of an electron microscope compare with that of an optical microscope which uses yellow

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

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The wavelength of a probe is roughly a measure of the size of a structure that it can probe in some detail. The quark structure of protons and neutrons appears at the minute length-scale of 10–15 m or less. This structure was first probed in early 1970’s using high energy electron beams produced by a linear accelerator at Stanford, USA. Guess what might have been the order of energy of these electron beams. (Rest mass energy of electron = 0.511

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

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Find the typical de Broglie wavelength associated with a He atom in helium gas at room temperature (27 °C) and 1 atm pressure; and compare it with the mean separation between two atoms under these

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

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Compute the typical de Broglie wavelength of an electron in a metal at 27 °C and compare it with the mean separation between two electrons in a metal which is given to be about 2 × 10–10 m. [Note: Exercises 35 and 36 reveal that while the wave-packets associated with gaseous molecules under ordinary conditions are non-overlapping, the electron wave-packets in a metal strongly overlap with one another. This suggests that whereas molecules in an ordinary gas can be distinguished apart, electrons in a metal cannot be distintguished apart from one another. This indistinguishibility has many fundamental implications which you

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

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Answer the following questions: Quarks inside protons and neutrons are thought to carry fractional charges [(+2/3)e ; (–1/3)e]. Why do they not show up in Millikan’s oil-drop

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

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Answer the following questions: What is so special about the combination e/m? Why do we not simply talk of e and m

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Answer the following questions: Why should gases be insulators at ordinary pressures and start conducting at very low

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Answer the following questions: Every metal has a definite work function. Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic? Why is there an energy distribution of

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

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Answer the following questions: The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relations: E = h ν, p = λ h But while the value of λ is physically significant, the value of ν (and therefore,

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

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A proton and an α-particle are accelerated, using the same potential difference. How are the deBroglie wavelengths λp and λa related to each

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

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In the explanation of photo electric effect, we asssume one photon of frequency ν collides with an electron and transfers its energy. This leads to the equation for the maximum energy `E_max` of the emitted electron as `E_max = hν – φ_0` where` φ_0` is the work function of

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

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Why is this fact (two photon absorption) not taken into consideration in our discussion of the stopping

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

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There are materials which absorb photons of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter

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

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Do all the electrons that absorb a photon come out as

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

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There are two sources of light, each emitting with a power of 100 W. One emits X-rays of wavelength 1nm and the other visible light at 500 nm. Find the ratio of number of photons of X-rays to the photons of visible light of the given

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

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Consider Fig. for photoemission. how would you reconcile with momentum-conservation? Note light (photons) have momentum in a different direction than the emitted

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

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Consider a metal exposed to light of wavelength 600 nm. The maximum energy of the electron doubles when light of wavelength 400 snm is used. Find the work function in

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

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Assuming an electron is confined to a 1nm wide region , find the uncertainty in momentum using Heisenberg Uncertainty principle (Ref Eq 11.12 of NCERT Textbook). You can assume the uncertainty in position Δx as 1nm. Assuming `p approx Delta p` , find the energy of the electron in electron

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

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Two monochromatic beams A and B of equal intensity I, hit a screen. The number of photons hitting the screen by beam A i twice that by beam B. Then what inference can you make about their

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

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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

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

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