In the double-slit experiment, the distance of the second dark fringe from the central line is 3mm. The distance of the fourth bright fringe from the central line is: In the double-slit experiment the distance of the second dark fringe from the central line is 3mm. The distance of the fourth bright fringe from the central line is: November 17, 2020 Category: Cengage NEET by C.P Singh , Chapter 16 - Wave Motion and Waves on a String , Part 1 , Facebook Messenger WhatsApp Share this:TwitterFacebook Related