Electro-pneumatic device

[quiet]

To describe the device more easily, the drawing shows the plates as if they were transparent.

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To avoid complications, let's suppose ideal conditions.

- Insulating cylindrical tube.

- Rigid plates of conductive metal, with negligible mass. To simplify, we will assume that the mass of each plate is equal to zero.

- Equal and opposite charges in the plates.

- The only thing that keeps the plates attached to the ends of the tube is the electric force of the capacitor.

- Both ends of the tube are sealed by the plates.

- An ideal gas has been injected into the tube, until it reaches the pressure that the plates can withstand. That pressure depends only on the electric force.

- Except for the inside of the tube, where there is gas, the rest of the device is in a vacuum.

- The device is at rest with respect to the reference system.

- Subsequently, the charge of the positive plate is neutralized by a negative charge of the same absolute value. The charge of the negative plate is not affected and remains constant.

- At the instant of neutralization, the electric force disappears in the neutralized plate. When does it disappear on the other plate? Does it happen strictly at the same instant or in a different one?

Edited September 16, 2018 by quiet

[studiot]

So how is the positive charge applied to one plate and how is it then removed 'instantaneously' ?

[Strange]

10 hours ago, quiet said:

At the instant of neutralization, the electric force disappears in the neutralized plate. When does it disappear on the other plate? Does it happen strictly at the same instant or in a different one?

This seems like an incredibly complicated setup to ask a simple question. 

Anyway, the answer is that the change  will propagate at the speed of light (or less).

Edited September 17, 2018 by Strange

[studiot]

13 hours ago, studiot said:

So how is the positive charge applied to one plate and how is it then removed 'instantaneously' ?

I asked this because I don't agree that the change can happen either instantaneously, or at the speed of light.

But I also think that the speed of change is not constant.

[quiet]

I want to thank the people who come to the thread.

Has pointed out strange that it is not an easy problem. I hope that makes it interesting.