Recently when I was procrastinating, I have learned that an electric energy is not propagated via wires but through fields. Once a circuit is closed, a field is created and it carries the energy from a source to eg a light bulb. It proposed a question to me.
The question is, how does the current/source know that the circuit has been closed?
Let’s ask two similar questions, both assume ideal conditions.
1. we have a source and a switch on Earth and a light bulb on Mars. We close the circuit using the switch and the energy starts to be emitted from the source in an almost instant. After some time, once the field reaches the bulb, it starts to emit light.
2. we have the same situation, but the switch is moved to Mars. Will it take the same time for the bulb to emit light? How does the source know that the circuit has been closed and it can start to emit and electric field?
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I assume it doesn’t. Energy typically travels from a higher potential to lower potential, and the source is enginerd to be at a high potential and the light bulb has lower potential. The fucking cool as nuts part is that as energy passes through the lightbulb, some of it is converted from a field of energy to a source of heat and light at the cost of some of that fields’ strength, current and whatnot. You could get rid of the lightbulb entirely and current will still flow when the two potentials are communicating, but what communicates the difference is probably gonna get a lil warmer, and that’s why wires need to be thick. But I’m not sure I am allowed to guess the answer to your post
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