Experiments
show that light has a dual nature; that is, as a particle and as a wave.
As wave : Light is a transverse wave can
propagate in a vacuum and have electrical and magnetic properties.
As particle : Light is emitted in discrete
packets of energy called quanta. Each quantum of energy is referred as photon.
With
the use of cesium clocks, the speed of light in a vacuum, c, is measured as
2.9979 x 108 m/s.
It is rounded as 3 x 108 m/s.
Light
can be absorbed, transmitted, refracted, reflected, dispersed, or scattered
when it encounters matter. A combination of this takes place in nature.
Reflection
– is the turning back of light to the
original medium from where it has been travelling after hitting a surface.
Reflection
from smooth surfaces is described as regular or specular, reflection from rough
surfaces is diffuse.
Refraction
-
The change in speed of light when it passes
from one medium to another.
When light speeds up
in passing from one medium to another, it is bent away from normal. When light
slows down, it is bent toward the normal.
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