1. The problem statement, all variables and given/known data Monochromatic plane waves of wavelength 537nm are incident on two narrow slits and produce an interference pattern on a wall 3.1m away. The slits are spaced 26 micrometers apart and are 5.7 micrometers wide each. What is the ratio of intensity to that of the central fringe a distance of 35.5mm from the central fringe? 2. Relevant equation I=I0(cos(∏(d/(λL)z)) 3. The attempt at a solution I tried using this formula to find the intensity of the central fringe and also the intensity of the fringe 35.5mm from the central fringe, however, I could not determine what I(sub)naught was.