Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The notion of coherence, introduced using pinhole diffraction. (a) A point-like source emitting only one wavelength always produces a visible fringes pattern. (b) If the emission is not a single wavelength but a band, the fringes may be washed out. (c) Likewise, if the source is not a point but has a finite area, the fringes may not be visible.
