Q1) Do electrons go first and only after they reached the other side the current appears? Or does the current appear first and it is the reason electrons start to move in the first place?
Q2) Is this the case for lightning too? If so, does it mean there is the current that goes from Earth to thunderclouds?
In: Physics
The reason for conventional current being positive to negative is because we discovered electricity long before we discovered the electron and have just stuck with it since. Doesn’t really impact anything important.
For an electric current to flow you need two things a potential difference and a resistance to connect the two. A potential difference is a difference between two or more energy levels, for example if you stood on the first floor of a building you’d have more potential energy than someone on the ground floor and we call that difference the potential difference or 1 volt if it was electricity rather than gravity. Some one on the second floor would have 2 volts relative to the ground and 1 relative to the first floor etc.
A resistor is something that connects two potential differences. If we have two pools of water side by side no water will flow between the two unless we have a potential difference and a connection between the two. So we could raise one tank up and put a hose between the two and bingo bango we have a water current that we could use to power something. The water started flowing as soon as the connection was made.
But hang on that won’t continue indefinitely. Either the top tank will run out of water or the bottom tank will fill up. So we could connect both to a pump that will send water back to the higher tank and complete our water circuit. That’s our power supply.
Q.2 lightning is a bit more complicated. Lightning is actually a change of state from a gas to a plasma, in the same way water changes state from ice to well water. I usually describe this process through a dinner party wedding event but don’t really have the time right now to go through it in full. But essentially a really large voltage exists between clouds and ground that causes a thing called electrical breakdown. When this happens the lightning is able to make a path to ground, it doesn’t follow the path of least resistance it actually makes a path of lower resistance.
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