Double-Slit Interference: Intensity Formula Derivation

This lecture covers the derivation of the intensity formula for the interference pattern produced by a double-slit setup with a large light wavelength and a distant screen. Starting from the general formula, a step-by-step process is followed to calculate the intensity at a point on the screen, involving the consideration of field amplitudes and phases from each slit. By simplifying the formula using geometric series and trigonometric identities, the final intensity formula is obtained, which is a generalization of the Young's formula for two slits. The lecture concludes with a clear explanation of the derived formula and its relation to Young's formula.