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Dual Nature of Radiation and Matter question

2013 · Q135
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Dual Nature of Radiation and Matter question

2013 · Q135

NEETPhysicsDual Nature of Radiation and MatterMCQ+4 / −1
A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct ?
  1. A
    The angular width of the central maximum will decrease.
  2. B
    The angular wifth of the central maximum will be unaffected.
  3. C
    Diffraction pattern is not observed on the screen in the case of electrons.
  4. D
    The angular width of the central maximum of the diffraction pattern will increase.
View written solutionFree

Correct answer: A

As speed of an electron increases.


Its de-Broglie wavelength decreases

λ=hmv\lambda = {h \over {mv}}λ=mvh​

and angular width for central maxima is ω\omega ω = 2λd{{2\lambda } \over d}d2λ​

ω∝λ∝1v\omega \propto \lambda \propto {1 \over v}ω∝λ∝v1​

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