How can the voltage between capacitor plates increase when separated?

This is the best physical explanation for why the voltage between plates increases as they are separated (if disconnected from the battery at least).

[theigcsechannel]

Why is this video a part of ET Physics A2-Level Playlist?

[larrydykes]

Nice! Enjoyed your setup and exposition.

[deeznuts-pflv]

I think the simplest and most intuitive explanation to this problem is that the oppositely charged plates are exerting an attractive force on each other. Since the plates are flat and the charge is evenly distributed, the force between the plates remains constant (at least upto a certain distance). Now if you pull the plates apart against this attractive force, the work you do would be stored in the charges as potential energy, which is exactly what voltage is: potential energy per unit charge. And the higher the potential energy, the faster the charges move when a path is provided for them to flow (a wire), which is what current is. So this is why pulling a capacitor's plates apart increases the voltage between them.

[cicaleapchem]

Epic explanation! I'd like to derive the function for electric potential vs position from a charged rectangular plate. How did you get that function that you mapped so well with Desmos?

[Kirti-ubzy]

C=Q/V=epsilon A/d
As distance increases, capacitance will decrease then potential should increase as charge is constant.

[meeharbin]

I would think that E near one of the plates would be higher when they are closer. As the other plate has a stronger repulsive/attractive force when it’s closer. I would expect E to stay the same.

[saraha]

can you please make some magnetism/optics review videos 🥺🙏 simply I would owe you my life

[Soldevi]

I thought this was due to v*a=w. a capacitor holds a certain amount of watts, and by separating the plates your reducing the amps, which in turn increases the volts as the watts always stay the same. you cant create or destroy energy but you can change its form. kind of like a compression of energy. people forget that 12v*10a=120w and 120v*1a=120w. there is no volt without amps, sometimes the amps are just to fast for us to measure.

[purinji_padipom]

I have a theory . maybe because positive and negative wants to be nearer because they are attractive and if we increase distance . then, we need to put work because they are attractive. Maybe this work stores as electrical potential energy and it increases . so, voltage increases

[westthsportstv]

Can you please make a video on AP Physics C mechanics and e&m review?

[u]

Everything given in this explanation is correct as far as I'm concerned. However, the late, great, Richard Feynman used to say that if you can only explain a phenomenon by writing down equations, then you don't really understand it....

Charges are dumb animals. Like charges repel each other. Unlike charges attract each other. The attraction and repulsion of charges follows an inverse square law. That's all charges "know" about themselves. In this experiment, no-one has told the charges that they'd better re-organise themselves to increase the voltage across a capacitor because someone has moved the plates further apart.

What is it that the voltmeter is actually measuring? In no direct sense is it is measuring how much work it would take to move a positive test charge of one Coulomb from the negative plate to the positive plate. So, the voltmeter doesn't know anything about potential energy. Potential energy is a derived term based on more fundamental measurements.

Suppose we discharged the capacitor through a torch bulb. The capacitor with the plates closer together would produce a dimmer flash than the one with the plates further apart. Why? You could say that the higher voltage caused a higher initial current as explained by Ohm's Law, but that wouldn't answer the question. The question is really about asking why do the electrons on the negative plate feel a higher pressure of attraction to the positive plate just because the plates are further apart, given that the strength of the electric field between the plates stays the same.

The electrons don't know anything about potential energy. They only know about forces of attraction and repulsion.

[erwinsan]

Very good explanation, teacher
But, my teacher wanted a physical explanation and not a mathematical one