A pair of slits separated by d = 1.30 mm is illuminated with light of l = 610 nm wavelength and falls on a screen L = 2.00 m away. A piece of glass with index of refraction n = 2.2 is placed at one slit. If the maxima shift is Dx/2, and falls on a minimum, what was the minimum glass thickness (in meters)? What I did: I first found Dx using the equation: Dx = lL/d and got an answer of 9.38*10^-4 Then because it says Dx/2. I divided that number by 2. After that, I wasn't sure which equation to use. The only equation that seemed likely was the t = (m + 1/2)λ/(2n) but in this equation, I can't use the number (Dx/2) that I've calculated. Am I using the right equation?