8th Class Science Chemical Effects of Electric Current Electricity Charge

        Electricity

Electricity, one of the basic forms of energy. Electricity is associated with electric charge, a property of certain elementary particles such as electrons and protons. Electric charges can be stationary, as in static electricity, or moving, as in an electric current.

Electricity is an extremely versatile form of energy. It can be generated in many ways and from many different sources. It can be sent almost instantaneously over long distances. Electricity can also be converted efficiently into other forms of energy, and it can be stored. Because of this versatility, electricity plays a part in nearly every aspect of modern technology. Electricity provides light, heat, and mechanical power. It makes telephones, computers, televisions, and countless other necessities and luxuries possible.

        Electric Charge

Electricity consists of charges carried by electrons, protons, and other particles. Electric charge comes in two forms: positive and negative. Electrons and protons both carry exactly the same amount of electric charge, but the positive charge of the proton is exactly opposite the negative charge of the electron. If an object has more protons than electrons, it is said to be positively charged; if it has more electrons than protons, it is said to be negatively charged. If an object contains as many protons as electrons, the charges will cancel each other and the object is said to be uncharged, or electrically neutral.

            Coulomb's Law

Objects with opposite charges attract each other, and objects with similar charges repel each other. Coulomb's law, formulated by French physicist Charles Augustin de Coulomb during the late 18th century, quantifies the strength of the attraction or repulsion. This law states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. The greater the charges on the objects, the larger the force between them; the greater the distance between the objects, the lesser the force between them. The unit of electric charge, also named after Coulomb, is equal to the combined charges of 6.24 x 1018 protons (or electrons).

             Charging by Induction

A charged object may induce a charge in a nearby neutral object without touching it. For example, if a positively charged object is brought near a neutral object, the electrons in the neutral object are attracted to the positive object. Some of these electrons flow to the side of the neutral object that is nearest to the positive object. This side of the neutral object accumulates electrons and becomes negatively charged. Because electrons leave the far side of the neutral object while its protons remain stationary, that side becomes positively charged. Since the negatively charged side of the neutral object is closest to the positive object, the attraction between this side and the positive object is greater than the repulsion between the positively charged side and the positive object. The net effect is an attraction between the objects. Similarly, when a negatively charged object is brought near a neutral object, the negative object induces a positive charge on the nearside of the neutral object and a negative charge on the far side. As before, the,ne't effect is an attraction between the objects. The induced charges described above are not permanent. As soon as the charged object is taken away, the electrons on the other object redistribute themselves evenly over it, so that it again becomes neutral..