Physic Labs

Problem 3

Two coherent in-phase sources of wavelength λ have path difference Δ at an observation point. Give conditions for interference maxima and minima. Use the stated ideal model: quantities are constant or vary only as specified, with no extra drag, losses, or external influences. State a sign convention, keep units consistent, and use a classical approximation only where appropriate. (a) Set up the governing equation from a fundamental law. (b) Solve for the requested quantity under the stated conditions. (c) Check the result using a suitable limit, sign, or unit test, and report both the expression and its physical meaning.At the observation point, I₁,I₂ are the individual wave intensities; k is an integer and δ is the phase difference.
cos⁡δ=−1⇒Δ=(k+1/2)λ\cos\delta=-1\Rightarrow\Delta=(k+1/2)\lambda
problems.proof.analysis

Substitute the intermediate result into the expression for the requested observable. Keeping parameters symbolic until this step makes dependencies clear and avoids premature rounding.