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

Answer

C

Explanation

As speed of an electron increases.
Its de-Broglie wavelength of decreases
`{lambda=(h)/(mv)}`
and angular width for central maxima is `omega=(2lambda)/(d)`
`omega prop lambda prop (1)/(v)`