Electricity
The earliest metal-conductive theory is the trud-lorenz theory based on classic theory. Assuming the presence of free electrons in metals, they follow the classic bolzmann statistics, like ideal gas molecules, and under balanced conditions, although they continue to move, the average speed is zero. When there is an external field, the electron accelerates in the direction of the field power a, thus creating a directional motion, whereby the electron loses its orientation by collisioning with the ion forming the crystal, thus having an average drift speedl at a certain level of power. According to the classic theory, the contribution of free electrons to the heat capacity in metals should be comparable to the heat capacity of crystal vibrations, but it was not observed in the experiment that this contradiction was resolved after understanding that electrons in metals are subject to the quantum statistics. And it was to resolve this contradiction, in conjunction with the development of quantum mechanics, that a systematic study of the movement of electronics in the crystal cycle field began to build up the theory. According to the energy chain theory, the electronics that move in a strict cyclical field are kept in the same state, and the electronics are not "retarded," except when the crystal field deviates from the cycle field for the reasons of atomic vibrations, impurities, etc., which cause the electronics movement to collide and disperse, thus giving the right explanation for the freeness of the electrons in the crystal. General metal resistance is caused by the dispersion of electrons by crystal atom vibration. The probability of dispersing is proportional to the squares of the atom shift, which is proportional to the temperature t at a sufficiently high temperature; at low temperatures, only those low-frequency crystal-temperature vibrations, i. E. Long acoustic waves, can contribute to dispersion, and as the temperature decreases, the number of contributing crystal-temperation patterns decreases, showing that metal resistance changes at low temperature limits. The modern theory of metal conductives has been developed on the basis of the femmy statistics and thesis. Its conductivity is considered to be 1 %1 `cm-1 ' . According to om's law, current density j in metals is higher than field strength e. The conductivity of metals is associated with temperature. Typically, metal resistance is precisely higher than temperature t. At low temperatures, the resistance rate of many metal materials varies according to t-regulated temperature. In the very low temperature of liquid helium, rare magnetic alloy materials containing trace magnetic impurities mostly show very small values on the lines of resistance to temperature variability. Metals are also a good conductor。
