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?

Home » 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?

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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?

Option A The angular width of central maximum will be unaffected
Option B Diffraction pattern is not observed on the screen in the case of electrons
Option C The angular width of the central maximum
Option D The angular width of the central maximum will decrease

Solution: Correct Option D

As the speed of electrons increases, the wavelength of electrons decreases, and the angular breadth () of the diffraction pattern’s center maximum decreases.
$λ = m v h$

and angular width for central maxima is $d 2 λ$

i

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