Lag1989 task number 20.50

Two beams of one light from one source arrive at the observation point P with the path difference Δ. Using a high resolution resolving power spectrometer, the energy distribution in the spectrum of the oscillation arising at the point P under the superposition of both beams is investigated. It turned out that alternating maxima and minima of the spectral intensity I (ν) are observed, and the frequency distance between neighboring maxima is Δν = 10 MHz. Determine the path difference Δν.