|MadSci Network: Engineering|
First, not that it concerns the answer, electricity in the form of current (electron flow) does not move at the speed of light, it is slower depending on the medium through which it flows. When you say "what comes out the other side", I presume you mean "how is the flow of electrons affected by the light bulb". (Although it is true that the electrons enter one side of a bulb and exit the other, it is the whole circuit that responds to the lightbulb. As a steady state flow scenario the whole circuit is affected at the same time, i.e. the electrons going in "know" about the backpressure caused by the bulb's presence, so they are kind of preconditioned due to its presence in their state of kinetic/potential energy levels and electrical field gradient.) What happens is the electrons initially have a certain energy level, they go into the bulb, the bulb emits heat and light, and the electrons continue in the circuit with less energy. The bulb emits the same amount of energy as was given up by the electrons going through it. In the form of the question you ask, the electrons come in at very forceful rate and exit at a lower forceful rate.
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