In Young's double slit experiment intensity at a point is `((1)/(4))` of the maximum intensity. Angular position of this point is

Options

A. (a) `sin^-1(lambda//d)`
B. (b) `sin^-1(lambda//2d)`
C. (c) `sin^-1(lambda//3d)`
D. (d) `sin^-1(lambda//4d)`

Answer

C

Explanation

`I=4I_0cos^2(phi//2)impliesphi=2pi//3`
`impliesDeltaxxx(2pi//lambda)=2pi//3impliesDeltax=lambda//3`
`sin theta=Deltax//d=sintheta=lambda//3d`