Download Light

Energy is the ability to do work.
There are two basic types of energy:
1. Kinetic Energy- The energy of motion. We use this
equation:
where m = mass of object
v = speed of object
2. Potential Energy- exists whenever an object
which has mass has a position within a force field.
We use this equation:
PEgrav = mass * g * height
What is it?
Electromagnetic Radiation (EM) Consists of oscillating
electric and magnetic fields (forces). Light is not composed
of matter. Light is energy. Light is composed of photons
(small packets of energy).
The energy of a photon
can also be written as:
E = hc/l
c is the speed of light in a
vacuum 3x108 m/s
And l is the wavelength
Duality of light
The concept of the photon brings to question the nature of light.
Light may act like waves rippling in space or the ocean. If so,
this represents the wave-like property of light with constructive
and destructive interference. Or light may act similar to a bullet
and actually cause matter be relocated. This represents the
particle like property of light. The latter property can be
explained by the Photoelectric effect.
If you use just the right
wavelength on just the right
material, the energy can be
transferred to the matter. In
some cases ejecting an electron.
This is how your remote control,
TV, microwave and many other
devices work.
Energy can be transformed
into matter with enough
speed.
E-
hv
Specific color of
light
Specific metal
Electromagnetic Radiation
the visible spectrum
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G
B
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E
R
E
R
L
N
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D
A
L
E
U
D
O
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E
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The human eye can only see the blend of colors. White
light is really composed all the above wavelengths.
The first clue to understanding the role of the electron in
the modern atom came from studying the line spectrum of
the elements.
Bohr imagined the electron moving around the nucleus in
circular orbits corresponding to various allowed energy
levels. Electrons can only be in “specific or discrete”
energy levels. All other values or “orbits” are not possible.
These levels are said to be “quantized”. The energy of an
electron can only change via a transition. They are not
continuous. Bohr’s model works well for hydrogen but
fails for heavier atoms.