Search
The Online Encyclopedia and Dictionary
Encyclopedia
Dictionary
Quotes
Emission
The word
emission
generally means sending something out. It can be used in the following contexts:
In
chemistry
emissions are the products of a
reaction
, either
chemical
or
nuclear
.
In
physics
and
physical chemistry
emissions are outputs of
electromagnetic radiation
or
particles
.
In common usage,
emission
is often the giving off of
gases
from
industrial processes
of
factories
and
transport
. As they occur on an industrial scale, even relatively harmless gases can have an undesired effect (such as
carbon dioxide
contributing to the
greenhouse effect
). See also
Emission trading
,
automobile emissions control
,
greenhouse gas
and
pollution
.
In the history of
optics
,
light
was supposed by adherents of
emission theory
to be emitted by the
eyes
.
Visual perception
was accomplished by such rays of light acting like feeling hands.
The contents of this article are licensed from
Wikipedia.org
under the
GNU Free Documentation License
. How to see
transparent copy