Electrotechnics: Basics


Electrifying bodies

The ability of bodies in the process of rubbing to accumulate electric charge, called - electrification. This occurs when rubbing amber. This means that the bodies are in a state electrical charges, but the bodies themselves are called charged. Note that the friction electrification process plays a fundamental role. Electric charges arise in intimate contact of various substances. In the case of solids friction allows to increase the area of mutual contact and thus increases the possibility of electrification. Two electrified bodies can either repel or attract each other. The capacity for such an interaction associated with the presence of electric charges on them of two types. Answer the question: "What is electric charge?" - It is impossible, but we can say for sure that the presence of an electric charge on the body leads to the ability of the electromagnetic interaction with other bodies, who also own this property.

If you charge the two light body suspended on silk threads, touching them with a glass rod, silk worn on, they repel each other. The same is observed if their charge from the ebony stick, worn on the skin. But if one of the bodies charged by the glass rod and the other on the hard rubber, they will be attracted. When electrified bodies repel each other, then we say that charges them a kind, when drawn, the charges of all kinds. Charges of different kinds are called positive and negative. It is considered to be a positive charge, which takes on the glass by rubbing it on the silk. Silk thus acquires a negative charge.

An important phenomenon that allows us to understand the process electrifying bodies, is the following, if the two bodies charged with opposite charges that are brought into contact, then after that the force between them or disappear altogether, or decrease, and change in the opposite direction. The charges of different signs cancel each other out. The phenomenon of the disappearance of a body called the electric charge neutralization. This fact suggests that any neutral body contains the same number of positive and negative charges. They do not occur by rubbing two bodies and redistributed between bodies, so that the first body (glass) is formed over the positive charges, and the second body (silk) - a surplus of negative. The electric charge of the charged body can be transferred to a neutral body, while the previous charge of the body will change.

What could be the smallest charge? Experiments show that none of the charged particles does not occur is less than the charge of an electron or proton charge. This basic charge is -1,60 • 10 -19 and an electron Cl + 1,60 • 10 -19 Cl proton. The charge of an electron is denoted by s, and proton - p. The mass of a proton, but in 1836 times the mass of the electron. It is also known that the electrons and the protons are part of each atom. Since protons are in the nucleus of atoms, the main role in the electrification of bodies electrons play. The so-called valence electrons, the most weakly bound to the nucleus, and some may even be outside of the atom. With close contact the two neutral bodies of the electrons can move from one body to another. If the body is formed over the electron, it has a negative charge. From the above discussion it can be concluded: the charges are not created or lost, they can be transferred from one body to another or moved within the same body. This provision is known as the law of conservation of electric charge, and is a major study of electricity. It can not be proved, but only confirmed by numerous facts and experiments. Sometimes it is formulated in a different way: in the isolated (closed) system, the algebraic sum of charges is constant.

Since every category q produced a set of elementary charges, it is an integer multiple of s

q=|n × e|

Electrometer

where n - the number of elementary charges extra. Equality shows that the electric charge - the value of a discrete, but the unit charge is so small that the possible magnitude of the charges can be considered a macroscopic changes continuously.

Usually, the term "charge" means a particle or body which is capable to electromagnetic interference.

Charged body, the size of which in this particular problem can not be ignored, called a point. In practice, in most cases, are charged macroscopic bodies.

To measure the magnitude of the charge on the body there is a meter - electrometer. With his contact with the metal rod of the electrometer of the charge goes to the attached axis conductive arrow and it is rejected. According to the angle of deflection is determined by the magnitude of the charge.

Date: 01.27.2016

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© Valentin Grigoryev


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