About a century ago there where no electric lights, motors, radios, and television sets. Today, electricity is in such common use that we tend to give it little thought. Although the practical application of electricity have been developed mostly in the twentieth century, the study of electricity has a long history.
Observations of electrical attraction can be traced back to the time of the ancient Greeks. It was Thales (640-540BC) who observed for the first time that a body could be made to attract other bodies by rubbing it with another bodies. Thales and others noticed that after amber has been rubbed, it attracts other subjects such as feather. The greek word for Amber is elektron.
Thus, a body made attractive is said to be electrified. This branch of electricity was earliest to be discovered and is know as electrostatics. Electrostatics is the study of electrical phenomenon that are associated with charges and charge systems at rest.
In this chapter, we will begin our study of electricity with a discussion on the concept of electric charges and how electric charge is associated with material bodies such as conductors and semi-conductors and insulators.
We will then study Columbus law which describes the force exerted by electric charge on another, after which we will introduce the concept of electric field and show how it can be described by the electric field lines which indicates the magnitude and direction of the field at any point. Lastly we will discuss the behavior of point charges including there motion in an electric field as well as electric dipoles in electric fields.
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