Wave Optics Part 2

A beam of light consisting of two wavelengths 7000Å and 5500Å is used to obtain interference pattern in Young's double slit experiment. The distance between the slits is 2.5‌mm and the distance between the place of slits and the screen is 150‌cm. The least distance from the central fringe, where the bright fringes due to both the wavelengths coincide, is n×10−5m. The value of n is ________