It is our intention to produce interference fringes by illuminating some sort of arrangement (Young\'s Experiment, a thin film, the Michelson Interferometer, etc.) with light at a mean wavelength of 500 nm, having a linewidth of 2.5 times 10^-3 nm. At approximately what optical path length difference can you expect the fringes to vanish? Solution Path length dt= 2/d=(500X10-9)2 /(2.5x10-3x10-9) Path length =0.1 m.