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Name: Connor
Status: student
Grade: 6-8
Location: IN
Country: USA
Date: N/A 


Question:
Where do electrons go after they have produced light in a light bulb?



Replies:
Connor,

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.

-Alex Viray


Hi Connor

Please click on the following URL and refer to this drawing of a light bulb:

Click Here

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.

Sincere regards,
Mike Stewart


Connor,

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,
Burr Zimmerman



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