In a YDSE experiment, the two slits are covered with a transparent membrane of negligible thickness which allows light to pass through it but does not allow water. A glass slab of thickness $t=0.41mm$ and refractive index ${\mu }_0=1.5$  is placed in front of one of the slits as shown in the figure. The separation between the slits is $d=0.30mm.$ The entire space to the left of the slits is filled with water of refractive index  ${\mu }_w=4/3.$  if A coherent light of intensity I and absolute wavelength $\lambda =5000A$ is being incident on the slits making an angle ${30}^0$ with horizontal if Screen is placed at a distance  $D=1m$ from the slits, the position of central maxima from point O on the screen will be (approximately)