kind of an attribute. Its most simple and intuitive performance for light to attract small objects (e.g. feathers, hair, debris), the object having such properties attract small and light object, with which said charge, or electrical tape. Electrical term comes from the Greek word "elektron", which means amber. As early as 600 BC there is friction on electrification of records, in 1600 the British physicist W · Gilbert found that not only the amber light friction can attract small objects, many other substances, such as diamond, sapphire, sulfur, hard resin and alum and other friction properties are also interesting light having small objects. He noted that after these substances do not have the friction properties of magnets that guide the North. Charge has three basic properties as follows: ① there are two charge nature - positive and negative charges; ② charge conservation; ③ charge quantization. Experiments show that the object or elementary particles may be positively or negatively charged, but they are equal to the electron charge, or charge carried by an integer multiple. Repulsion between the same kind of charge attraction between dissimilar charge. When the center of gravity equal but opposite charge distribution coincides its external electrical effects cancel each other and are neutral, it is considered to be uncharged. The presence of an electric field around the charge, while the presence of a magnetic field around the moving charge; the charge subjected to an electric field of electric force, moving charge in a magnetic field subjected to magnetic force.
in the molecule due to the inherent dielectric strength of the charged particles can not be bound molecules macroscopic displacement occurs. Under the action of an external electric field, the charged particles can be constrained to make microscopic movement, polarized charges macroscopic dielectric effect small displacement caused by the bound charges. Also referred to as polarized charges bound charge.
external electric field, the dielectric properties of an electrical phenomenon displayed. Under normal circumstances, it does not exhibit macroscopic electrical dielectric. External electric field, the local mobile bound charge causes it exhibits macroscopically electrically, and the electrical surface inside the medium occurs unevenness in the macro-charge, this phenomenon is called polarization. This occurs because the polarization charge is called macroscopic polarization charge (also referred to as bound charge). Polarized charges in the voxel △ ι divided △ ι is the polarization charge density of the point. Similarly, the presence of polarization charge density in the plane of polarization of the dielectric surface. For clarity, the macroscopic polarization caused by a charge is not due to be called free of charge. Such as a dielectric due to friction or contact with live parts and the conductor exhibits macroscopic charge loss or gain due to the free electron charge macro presented belong free charge. Press polarization microscopic mechanism, can be divided into: the displacement of the polarization of the molecule and polar alignment of the molecular polarization electrode. There are two displacement polarization cases, one such as H 2 , N 2 gas molecules, etc., since the electronic mass is much smaller than nuclear mass. Under the action of the electric force, an electronic moved a displacement in the gravity field strength in the opposite direction. Each molecule is formed by a small electric dipole, electric dipole electric dipole moment pαE, and lined up (FIG. 1) in the direction of the external electric field. This polarization of polar molecules often referred to as electronic displacement polarization. Another type of CKS is a dielectric field by the outer positive and negative ions consisting of strong positive and negative ions along the field direction moved by a displacement, an electrical dipole, electric dipole electric dipole moment pαE, which results As shown in FIG. 1, this polarization is called ion polarization. Results displacement medium is uniformly polarized plane of polarization charges appear on the surface. Dielectric polar molecules, each molecule has an electric moment p, but in the absence of external field, due to the thermal motion of macroscopic electrically significant. External electric field, the electric moment p per molecule are subjected to a torque is applied, the electric moment of the molecule steering direction E, but due to thermal motion, this orientation is not complete, i.e., all molecular dipoles are not very neatly along the outer field direction are arranged (FIG. 2).
Of course, E is stronger, the orientation of the more neatly. This mechanism is known as orientation polarization polarization. - uniform orientation of polarization plane of polarization charge media are present in the surface. Displacement of polarization exists in any dielectric polarization, the polarization is oriented only to the presence of polar molecules. However, the dielectric consisting of polar molecules, the orientation of the polarization ratio Polarization displacement about an order of magnitude, and therefore the main polarization orientation. In the high frequency electric field, due to the inertia of the larger molecules, the orientation of the external electric field polarization keep up with changes, and the electron inertia, so this time, no matter what kind of dielectric polarization mechanism only from the displacement of the electron effect. Two point system magnetic charges
have equal and opposite magnetic dipole is referred to. For example, a small needle can be viewed as a magnetic dipole. The magnetic field may be regarded as a magnetic field generated by the dipole. Action by the magnetic dipole moment of rotation can occur only when the torque is zero, the magnetic dipole will be in equilibrium. Using this principle, the magnetic field can be measured.
subatomic scale small magnet, which is equivalent to the charge flowing around the circuit. Electrons around the nucleus movement, about its axis of electrons and nuclei rotary magnetic dipoles are positively charged. Iron atom spontaneously formed by arranging the same composition as the ferromagnetic domains also form a magnetic dipole. Needle bar permanent magnet and a macroscopic magnetic dipole. Strength of the magnetic dipole magnetic dipole moment is called, it can be seen as a measure of the rotation of the dipole energy of the applied magnetic field aligned along a direction. Feel the magnetic dipole moment acting in a magnetic field, and it itself generates a magnetic field. When the freely rotating magnetic dipole, magnetic dipole moment which is the main point of the direction of the external magnetic field.