[Physics] Where does energy in electricity come from


In a simple battery-wire-lightbulb circuit the moving electrons in a wire generate electromagnetic field, and that field transports energy. And the bulb goes light.

But where does the energy come from in the first place? It obviously cannot be 'generated' because of the conservation law, so it has to previously be some other form of energy?

Is the energy photons radiated by moving charges? But the electrons would be going down energy levels, and then somehow going up again, only to 'discharge' all over again. And I get from the pop-sci articles all over the web that it's exactly what does not happen, an electron is not an 'energy bucket'. But then again it sort of has to be, as it actually loses the energy, via heating the tungsten filament in the lightbulb?

In most (all? what about moving a magnet in a coil?) circuits we'd have a potential difference, and I read somewhere there is a potential energy associated with it. Is it all this energy's 'fault'? Does it get transformed into kinetic energy that gets the charged particles moving, and also in bigger part to the E-M field energy 'bound' to these charges? Is there a mechanism through which this energy transformation is done, or is it a stupid question, it just gets transformed and that's it?

What if we move a magnet inside a coil – then we get particles moving, but no potential difference (or is it an invalid conjecture, and PD is there somewhere?)

It's all very confusing, sorry once again if these questions are stupid.

Best Answer

But where does the energy come from in the first place?

The battery converts energy from one form to another. A charged battery stores potential chemical energy (which is, fundamentally, electric in nature) and converts it to electrical energy by, if you will, "pumping" electrons through an external circuit.

Now, you may well ask "yes, but where did the chemical energy from?".

In other words, when you specify "in the first place", that's quite a chain to reckon with that, I suppose ends with the big bang.

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