1. The problem statement, all variables and given/known data A horizontal beam of laser light of wavelength 474 nm passes through a narrow slit that has width 5.80×10−2 mm . The intensity of the light is measured on a vertical screen that is 2.40 m from the slit. Use the result of part A to estimate the width of the central diffraction maximum that is observed on the screen. (Part A: What is the minimum uncertainty in the vertical component of the momentum of each photon in the beam after the photon has passed through the slit? I got this part.) 2. Relevant equations $$\theta = \arcsin(\lambda/a)$$ $$y = d * \tan\theta$$ 3. The attempt at a solution I just used the two equations above first to get theta and then to get y and times y by two to get the central diffraction maximum but that's wrong. I'm missing at which part I'm supposed to use the minimum uncertainty. Can anyone explain, please?