In a double slit experiment, the distance between slits in increased ten times whereas their distance from screen is halved then the fringe width is

Options

A. becomes `(1)/(20)`
B. becomes `(1)/(90)`
C. it remains same
D. becomes `(1)/(10)`

Answer

A

Explanation

Fringe width, `beta=(D lambda)/(d) " "` … (i)
According to the question, `D'=(D)/(2)` and `d'=10d`
` :. beta'=(D'lambda)/(d')=((D//2)lambda)/(10d)=(1)/(20)=(D lambda)/(d)`
` implies beta'=(beta)/(20) " " ` (Using (i))