Answer to Question #122080 in Optics for Mio

Question

How can a single slit cause interference in light?

Answer 1

We observe interference in normal double-slit experiment because two sources of waves interfere with one another. We can observe a single-slit interference because every piece of the wave that passes through the slit can be represented as the infinite number of wave sources. Since the distance to the screen is different for any of these infinitesimally small sources, we observe interference even with a single slit.