Electrostatics Of Conductors- There are two types of charges: positive and negative. Like charges repel and opposite charges attract.
There exist in nature two types of charges: positive and negative. The force between them is such that like charges repel and opposite charges attract. For example, two positive charges brought near each other will be pushed away from each other. On the other hand, one positive charge and one negative charge brought near each other will be pulled towards each other. It is this principle on which all
electrostatics is based.
Each type of material has a different arrangement of atoms, electrons, and protons. The particular arrangement of a material's atoms can be very advantageous for electric charge to travel through it. Metals, for instance, are very good conductors. Charges can flow through a metal with very little resistance. The particular arrangement of a material's atoms can by disadvantageous, however. Rubber, for instance, has its atoms arranged such that it is very difficult for electric charge to flow through it.
Rubber is considered to be an insulator.
A person's body allows electric charge to travel through it easily. It is for this reason that one must be careful not to plug in the radio while in the bathtub: electric charges from the outlet can run through your body, electrocuting you.
- When certain types of materials are rubbed against other certain types, charge may be transferred from one to the other.
Each object contains charge. For most objects, the number of negative charges equals the number of positive charges, giving a net charge of zero. These charges are free to move, however. When certain types of materials are rubbed against each other, the material's atoms are arranged such that some of the charges from one material will be transferred to the other material. This gives both objects a net charge. One object will be positively charged, the other will be negatively charged. For example, when a teflon rod is rubbed against silk, charge is transferred.
- When an uncharged object is placed near a charged object its charges rearrange themselves. Those charges attracted to the charged object move towards the charged object and those charges repelled move away. This effect is known as polarization.
As discussed before, most objects are uncharged. An
uncharged object means that the total number of positive charges equals the total number of negative charges. The net charge on the object is zero. When an uncharged object is polarized as described above, its net charge remains zero. No additional charge is put on the object. What does happen, however, is the charges inside the object rearrange themselves. When a negatively charged object, for instance, is placed near an uncharged object, the negative charges move away from the charged object and the positive charges move towards the charged object. It is this effect that makes the uncharged object act as if it is charged.
- Charges on a conductor tend to gather at sharp points.
For several complex reasons, the charges on a conductor will gather at sharp points. A metal cone, for instance, which has been charged will have a lot of charge at the point, and much less charge elsewhere.
No comments:
Post a Comment