I know, that voltage is analogous to pressure for charge, but analogies lie. I d
ID: 1382389 • Letter: I
Question
I know, that voltage is analogous to pressure for charge, but analogies lie. I don't see charge pressing anything and I don't understand definition of U=A/q (voltage = work/charge), cause I can't see what is that work.
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Voltage in a circuit is determined by an accumulator. I suppose, that accumulator is characterized with voltage output and current output. I don't get how they are related, but can imaging some tweaks to the accumulator:
1) If I double the area of both metal plates, contacting with respective solutions, would it double the voltage output? Intuitively it will cause twice the amount of Ions bump into plates and give their charges to them, so it would double the current and won't change any "charge pressure", I can think of.
2) If I double the concentration of each solution, would it double the current or charge. My intuition that it is the same as if I doubled the area of plates - it would just double the amount of ions transferring their charge per moment of time. Nernst equation suggests a change of voltage in this case, but I can't see what it is.
What I want to understand, is what is voltage in terms of ball-like ions, forces and such intuitive entities. Thanks.
Explanation / Answer
1) If I double the area of both metal plates, contacting with respective solutions, would it double the voltage output?
No, the voltage is dependent on the chemistry. "D" and "AAA" sized zinc-carbon cells both produce about 1.5 volts.
Bigger batteries can produce larger currents. This is presumably because a larger electrode surface area allows for a greater number of ions to be reacted with.
If I double the concentration of each solution, would it double the current or charge.
It would increase the charge. Empirically you measure the charge in a lead-acid battery by measuring the specific gravity of the electrolyte. There are limits to how concentrated a solution can be. A fully-charged lead-acid battery contains sulphuric acid, a fully discharged lead-acid battery contains water.