Questions

# 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?

## Unlock the full solution & master the concept.

Get a detailed solution and exclusive access to our masterclass to ensure you never miss a concept
By Expert Faculty of Sri Chaitanya
a
The angular width of the central maximum will decrease.
b
The angular width of the central maximum will be unaffected.
c
Diffraction pattern is not observed on the screen in the case of electrons.
d
The angular width of the central maximum of the diffraction pattern will increase.

Check Your Performance Today with our Free Mock Tests used by Toppers!

detailed solution

Correct option is A

de Broglie wavelength of an electronλ=hp=hmvwhere m is the mass and v is the speed of the electron respectively.If speed v of electron is increased, momentum p (= mv) will increase. Hence, wavelength λ will decrease.Angular width of the central maximum is θ0=2λawhere a is the width of slit.If λ  decreases, θ0 will decreaseTherefore, the correct statement is (a).

Similar Questions

In single slit diffraction pattern under bichromatic illumination. If the first minimum with the wavelength $\mathrm{\lambda }$1 is found to be coincident with third maximum of $\mathrm{\lambda }$2, then

Get your all doubts cleared from
Sri Chaitanya experts

+91