### Wave optics: Young's double-slit experiment

In a Young's double-slit experiment the separation y between the second-order bright fringe and the central bright fringe on a flat screen is 0.0180 m, when the light has a wavelength of 425 nm. Assume that the angles that locate the fringes on the screen are small enough so the sin(theta) ~ tan(theta). Find the separation y whe