Electron Location After Light Bulb
Where do electrons go after they have produced light in a light
Light is emitted from an electron as it returns to its equilibrium
state in the atom. The energy to produce light, called photons, is
gained when the electron jumps from one energy band level to another.
As the electron returns to its stable state, the energy gained is
released in the form of light. The mechanism that excites an electron
to jump from one energy level to another is different for each type of
light source. But the electron path, and its energy emission in the
form of light, is the same.
Please click on the following URL and refer to this drawing of a light bulb:
To make light, electrons come in at the electrical contacts at the bottom of
the bulb; go up the connecting wires
pass through the coiled tungsten filament
then go down the other end of the connecting wires
out the electrical contact at the bottom of the bulb.
The electrons come into the bulb with a high energy level (voltage)
Dissipate their energy in the tungsten filament as heat and light
And leave at a lower energy level to the ground.
It is a common misconception that electrons "turn in to light" in a
light bulb, but that is not what actually happens. There is a lot of
energy in household electricity. As electricity flows through the
light bulb, some of the energy in the electricity is taken by the
light bulb and transferred in to heat and light. To explain how
his works, let me use an analogy.
Imagine a huge boulder on a hill, and imagine you roll the boulder
down the hill. As it is rolling down the hill, it gains speed. If it
gets rolling really fast, it can hit a smaller rock or a log cabin and
send that object flying. After the collision, the boulder is going
slower, but it still keeps rolling down the hill.
With the light bulb, electricity is like the boulder. Voltage is the
force that drives electricity -- it is the "gravity" for the boulder in
the example. The light the bulb creates is like the object that goes
flying when hit by the boulder. As the electricity flows through the
light bulb, down the voltage "hill", it "bumps in to" the filament
inside the light bulb.
Technically, this is not a elastic collision like the boulder, but
it is a convenient way to think about how some of the energy from the
electricity is converted to heat and light, while the rest of the
energy stays in the electrical current.
The filament takes some of the energy from the
electricity, which causes the filament to heat up and give off light.
A "circuit" refers to the fact that electricity needs a path to follow
from high voltage to low voltage (like the bolder will not move if
there is an obstruction in front of it).
Hope this helps,
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Update: June 2012