In a Young's double slit experiment, three polarizers are kept as shown in the figure. The transmission axes of  $$P_1$$  and  $$P_2$$ are orthogonal to each other. The polarizer  $$P_3$$  covers both the slits with its transmission axis at  $$45^\circ$$  to those of  $$P_1$$  and  $$P_2$$. An unpolarized light of wavelength  $$\lambda$$ and intensity  $$I_0$$  is incident on  $$P_1$$  and  $$P_2$$.The intensity at a point after  $$P_3$$  where the path difference between the light waves from $$s_1$$  and  $$s_2$$  is  $$\frac{\lambda}{3}\text{ is:}$$