Example 7.3: Plane wavefront of light of wavelength 5500 A is incident on two slits in a screen perpendicular to the direction of light rays. If the total separation of 10 bright fringes on a screen 2 m away is 2 cm, find the distance between the slits.P Example 7.4: In a Young's double slit experiment, the difference in optical path T lengths between the rays starting from the b two slits S, and S, and reaching a point A T on the screen is 0.0075 mm and reaching another point B on the screen on the other side of the central fringe is 0.0015 mm. How many bright and dark fringes are observed between A and B if the wavelength of light used is 6000 A