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?

Options

A. the angular width of the central maximum of the diffraction pattern will increases
B. the angular width of the central maximum of the diffraction pattern will decrease
C. the angular width of the central maximum will decrease
D. diffraction pattern is not observed on the screen in the case of electrons

Answer

B

Explanation

` theta=(lambda)/(d)`
According to de Broglie
`lambda=(h)/(mv)`
`:.` If velocity of electron is increases its wavelengths decreases and therefore, its angular bandwith also decreases.