Modern Physics for Engineers Lecture slides 07a – Waves, diffraction and uncertainty

This lecture part introduces the idea of uncertainty principles, first by using a classical uncertainty principle common for most kinds of waves - the (inverse) relation between the size of an aperture and the diffraction angle or "spread" of the wave. When applied to quantum mechanical waves, we can justify the Heisenberg uncertainty principle. The meaning of the uncertainty principle in quantum mechanics is often unfortunately mixed up with the difficult issue of measurement in quantum mechanics and the "collapse of the wavefunction". (slides)