In a modified Young's double-slit experiment, source S is kept in front of slit `S_(1)` as shown in the following figure. Find the phase difference at a point that is equidistant from slits `S_(1)` and `S_(2)` and point P that is in front of slit `S_(1)` in the following situations:

If a liquid of refractive index n is filled between the screen and slits, what is the phase difference?

Options

A. `(2pi)/(lambda)[[sqrt(d^(2)+x_(0)^(2))+x_(0)]+(nd^(2))/(2D)]`
B. `(2pi)/(lambda)[[sqrt(d^(2)+x_(0)^(2))-x_(0)]+(nd^(2))/(2D)]`
C. `(2pi)/(lambda)[[sqrt(d^(2)-x_(0)^(2))+x_(0)]+(nd^(2))/(2D)]`
D. `(2pi)/(lambda)[[sqrt(d^(2)-x_(0)^(2))-x_(0)]+(nd^(2))/(2D)]`

Answer

B