Wave optics (part-2)

What is Fringe Width? How to derive the interference of Light waves and young’s experiment? How to draw the intensity distribution curve interference pattern? How to obtain the fringe width in interference method?

To get Wave optics (Part-1) Click Here

Thomas Young let a ray of sunlight into a dark room, placed a dark screen in front of it, pierced with two small pinholes, and beyond this, at some distance, a white screen. He then saw two darkish lines at both sides of a bright line, which gave him sufficient encouragement to repeat the experiment, this time with spirit flame as light source, with a little salt in it to produce the bright yellow sodium light. This time he saw a number of dark lines, regularly spaced; the first clear proof that light added to light can produce darkness. This phenomenon is called interference. Thomas Young had expected it because he believed in the wave theory of light