A beam of electron is used `YDSE` experiment . The slit width is d when the velocity of electron is increased ,then

Options

A. no interference is observed
B. fringe width increases
C. fringe width decreases
D. fringe width remains same

Answer

C

Explanation

When velocity of electron increases, the momentum of electron `(p = mv)` increases. The de-Broglic wavelength `lambda(h//mv)` decreases. The fringe width is `beta = lambda D//d`, so `beta prop lambda`. Hence if `lambda` decreases, `beta` decreases.