Electrostatics is a branch of physics that deals with the phenomena and properties of stationary or slow-moving electric charges with no acceleration. Since classical physics, it has been known that some materials such as amber attract lightweight particles after rubbing.
Electrostatic phenomena arise from the forces that electric charges exert on each other. Such forces are described by Coulomb’s law. Even though electrostatically induced forces seem to be rather weak, the electrostatic force between e.g. an electron and a proton, that together make up a hydrogen atom, is about 36 orders of magnitude stronger than the gravitational force acting between them.
|Topical Notes, Quiz, Test, Resources, Presentation, Problems, and Solutions|
|Electric Charge and Its Conservation; Insulators and Conductors; Induced charge and the Electroscope;|
|Electric Force and Coulomb’s law|
|Electric Field, Field lines; Motion of a Charged Particle in a Uniform Electric Field|
| Chapter 1: Test your Understanding
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Electrostatics involves the buildup of charge on the surface of objects due to contact with other surfaces. Although charge exchange happens whenever any two surfaces contact and separate, the effects of charge exchange are usually only noticed when at least one of the surfaces has a high resistance to electrical flow. This is because the charges that transfer to or from the highly resistive surface are more or less trapped there for a long enough time for their effects to be observed. These charges then remain on the object until they either bleed off to ground or are quickly neutralized by a discharge: that is the familiar phenomenon of a static ‘shock’ is caused by the neutralization of charge built up in the body from contact with insulated surfaces.
Today’s synthetic materials are well-known for becoming charged very easily so that cars and carpets can give quite a nasty shock. Try separating bed-clothes in the dark of night and you will really see sheet lightning!
In modern laboratories with water fed through plastic pipes, it may be very difficult to find any point electrically bonded to earth. In such cases, an earth for electrostatics experiments can be provided by burying a substantial metal rod in the ground with a wire running through the wall to a terminal in the laboratory.
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