Two glass plates are separated with fine wires, with diameters d1 = 0.0500 mm and d2 = 0.0520 mm, as indicated in the figure. The wires are parallel and separated with a distance of L =6.80 cm. If monochromatic light with λ = 500 nm is incident from above, what is the distance among adjacent dark bands in the reflected light? (Consider interference only among light reflected once from the bottom surface of the upper plate and light reflected once from the upper surface of the lower plate.)