Interference (Physics)

Recall cards on the wave interference of light. Young's double-slit experiment: coherence versus incoherence, constructive and destructive interference, fringes, and the historical evidence for the wave nature of light. The mathematics of interference: path length difference delta-l = d sin(theta), bright fringes at d sin(theta) = m*lambda, dark fringes at d sin(theta) = (m + 1/2)*lambda, order m, and the fringe position y_m = m*lambda*D/d. Multiple-slit interference: principal maxima, the N minus 2 secondary maxima, secondary-maximum amplitude 1/N and intensity 1/N^2, and the diffraction grating. Interference in thin films: the 180-degree phase change on reflection off a higher-index medium, the in-film wavelength lambda_n = lambda/n, and the soap-film constructive and destructive conditions. The Michelson interferometer: the beam splitter, the fringe-shift relation 2*delta-d = m*lambda_0, the compensator plate, and its use in precision measurement.