3:43, why there is no electric field inside the conducting plate due to the "static situation"? Also, the electrons move initially (until the electrons move) due to induction, causing current flow (top to bottom) right?
I believe what looks like a second square plate in v=UtPtMltV4DY is really plastic, or covered in a plastic. I don't know if he is touching the plastic with his thumb, or that small silvery rectangle on the lower left, which might be a separate ground? I think he is just grounding the top of the round conductor and what he is touching with his thumb isn't necessary, he would be an efficient enough ground.
When you touch the plate, why don't the electrons from ground reach the plate , neutralize the positive charge and make the plate "negatively charged" ?
When the metal plate is sitting on the charged plastic, the positive charge on the bottom of the metal plate is held in place by the negative charge on the plastic. So when I touch the top of the metal plate, I provide a path for positive charge to flow on to the plate and neutralize the negative charge on the top of the metal plate. So you can think of the ground as providing positive charge to the metal plate. Ground is an infinite source of negative or positive charge.
The earth is an electron reservoir. If an object is grounded, the earth can either a) take electrons from a negatively charged object to neutralize its charge b) give electrons to a positively charged object to neutralize its charge The charge of the earth is zero.
Sorry I did not see your comment till today. A ground is an infinite supply of negative, or positive, charge. So the earth is a good ground because it is so large adding or removing charge does not change the earth's potential. So even if something has a net charge, if it can still supply an infinite source of negative or positive charge it will be an effective ground.
What if I don't touch the upper plate?I mean I will do the whole experiment without touching the upper plate,i.e. to say without providing the grounding.What will happened in that case?
You would probably have very little charge on the plate. Some of the electrons from the plastic would transfer so you would have a small net negative charge, rather than a large net positive charge, on the plate.
Hi Michael, is there an electrostatic force-field in between the plastic plate and the metal conductor causing the two plates to repel one another? Is that why there are only a few contact points and why the electrons don't flow onto the conductor?
If you zoom in on the surfaces of the plastic and metal disk, you would find that they are rough, they might look a little like a mountain range. So when you put the metal disk on the plastic there will only be limited amount of actual contact. The electrons on the surface of the plastic cannot flow to these contact points, and then onto the metal disk, because the plastic is not conducting.
can you plz help to explain how this type of electrophorus works? watch?v=UtPtMltV4DY The person in that video is grounding both plates at the same time and still gets the charge separation.. thanks
Where is the demonstration? We see -- and hear -- only the explanation. It is very strange to see to be felt the explanation of a fact much-much more important than its "demonstration", i.e. the fact itself.
