A Michelson interferometer uses light from a sodium lamp. Sodium atoms emit light having wavelengths 589.0 nm and 589.6 nm. The interferometer is initially set up with both arms of equal length (L₁ = L₂), producing a bright spot at the center of the interference pattern. How far must mirror M₂ be moved so that one wavelength has produced one more new maximum than the other wavelength?