Charges & Insulators: Answers to Questions

[aeacus]

First question i have is about the common glass rod-cloth experiment where the one gets plus charged and the other minus charged.The plus charged item how does it get back the electrons that it missed?If we touch it again with the other one or even through the air?And the minus charged how does it release its additional electrons?

Secondary i want to ask something about insulators.I know that if we apply a potential difference through an insulator its electrons have strong bonds with each nucleus so we have few free electrons and so it is a non conductor.If we put an insulator though in the middle of a circuit,for example a plastic item that has a metal wire connected to its one end and another wire to its other end and both wires are connected to a battery,then few of insulators electrons will move but will wire's electrons run through the insulator?If yes or not please explain the reason.

Thanks in advance

 

[Delta2]

First question i have is about the common glass rod-cloth experiment where the one gets plus charged and the other minus charged.The plus charged item how does it get back the electrons that it missed?If we touch it again with the other one or even through the air?And the minus charged how does it release its additional electrons?

Yes if we touch the items for a brief period of time (without rubbing them against each other) the additional electrons will get attracted by the positive ions and both items will return to neutral charge.
In general if we bring the charged item in contact with any other item charged or not (which is not a perfect insulator) there will be moving of electrons between the two items (from the item with the lower potential to the item with the higher potential), until both items are in same potential (or until the free electrons in the item with the lower potential have been exhausted, that is the case where the item is bad conductor and there is really big potential difference between the two items).
Ofcourse you might ask me here what is potential and potential difference. This would be hard to answer without getting into mathematic details. Potential depends not only on the amount of charge one item has but also how this charge is distributed inside or at the surface of the item. We can say that the item which is more negatively charged is in lower potential however this is not always the case.

Secondary i want to ask something about insulators.I know that if we apply a potential difference through an insulator its electrons have strong bonds with each nucleus so we have few free electrons and so it is a non conductor.If we put an insulator though in the middle of a circuit,for example a plastic item that has a metal wire connected to its one end and another wire to its other end and both wires are connected to a battery,then few of insulators electrons will move but will wire's electrons run through the insulator?If yes or not please explain the reason.

Thanks in advance

Well what you actually do is forming a circuit in series with the battery the insulator and the wires. In a circuit in series , the current is everywhere the same. Because of that and because the current in insulator will be small, the current at the contacts between the wires and the insulator will also be equal small, so very few electrons from the wire will move through the insulator and from the insulator through the other wire.

http://en.wikipedia.org/wiki/Series_circuit

 

[aeacus]

Okay thanks.In the first question though,if we don't just touch the differently charged items to restore the balance how will they become neutral again?Through the air?

 

[Delta2]

Okay thanks.In the first question though,if we don't just touch the differently charged items to restore the balance how will they become neutral again?Through the air?

If the charge in the item is small (and it is small in the rod-cloth experiment), it can become neutral by getting opposite charges through the air. Air is a very good insulator though so (similar to your 2nd question) there would be very few electrons or even positive ions flowing through air.

 

[sardar]

I can provide some explanations for your questions about charges and insulators.

Regarding the common glass rod-cloth experiment, when we rub the glass rod with cloth, electrons from the cloth are transferred to the rod, giving it a negative charge. At the same time, the cloth becomes positively charged due to the loss of electrons. When we touch the rod with the cloth again, the electrons from the cloth will transfer back to the rod, neutralizing its charge. This transfer of electrons can also happen through the air if the two objects are close enough to each other. As for the negatively charged object, it will release its extra electrons when it comes in contact with a positively charged object, such as the cloth in the experiment.

Moving on to your question about insulators, you are correct in saying that insulators have strong bonds between their electrons and nuclei, making them poor conductors of electricity. In the scenario you described, if we place an insulator (such as a plastic item) in the middle of a circuit, the electrons in the wire will not be able to flow through the insulator. This is because the electrons in the insulator are tightly bound to their nuclei and cannot move freely like in a conductor. However, if the voltage applied is high enough, the insulator can become ionized and allow some electrons to flow through it. This is known as breakdown voltage.

In summary, the movement of charges and the behavior of insulators are determined by the balance of attractive and repulsive forces between electrons and nuclei. When these forces are disrupted, such as through rubbing or applying a high voltage, we can observe the transfer of charges and changes in the insulator's properties. I hope this helps to clarify your questions.