English Wikipedia - The Free Encycl...
Download this dictionary
Pencil (optics)
In
optics
, a
pencil
or
pencil of rays
is a geometric construct used to describe a
beam
or portion of a beam of
electromagnetic radiation
or charged
particle
s, typically in the form of a narrow
cone
or
cylinder
.
See more at Wikipedia.org...
© This article uses material from
Wikipedia
®
and is licensed under the
GNU Free Documentation License
and under the
Creative Commons Attribution-ShareAlike License