1. The problem statement, all variables and given/known data In a KhanAcademy video, light of wavelength 700nm shines through a double-slit whose holes are spaced 1300nm apart. If a screen is placed 3m away from the double-slit, what will be the distance from the central bright spot on the screen to the next bright spot? https://www.khanacademy.org/test-pr...agnetic /v/youngs-double-slit-problem-solving 2. Relevant equations per KhanAcademy: d*sinθ = m*λ per what I think: Y = R*m*λ / d d = distance between the 2 slits m = whether it's the 1st, 2nd, 3rd bright band Y = distance from central bright R = distance from double-slit to screen 3. The attempt at a solution per KhanAcademy and using d*sinθ = m*λ d*sinθ = m*λ 1300nm*sinθ = 1*700nm sinθ = 700nm / 1300nm θ = 32.6° then use this to find Y tanθ = Y / X Y = tanθ*X Y= tan(32.6°)*3m Y= 0.64*3 Y= 1.92m per what I think and using Y = R*m*λ / d Y = R*m*λ / d Y = 3m*1*700nm / 1300nm Y = 1.62m (nanometers were converted to meters. I just did it this way to save space when typing it here) My Question: Which equation should I use? Why am I getting different answers?