Question
A thin glass plate of thickness is $\frac{{2500}}{3}\,\lambda $ ($\lambda $ is wavelength of light used) and refractive index $\mu = 1.5$ is inserted between one of the slits and the screen in Young's double slit experiment. At a point on the screen equidistant from the slits, the ratio of the intensities before and after the introduction of the glass plate is
