Electric current in various media
One of the most important definitions of physics is thatan electric current is any ordered motion of particles having any charge. From this it can be concluded that in order for the electric current to appear, it is necessary to have free electrons or ions in the metal, liquid, or some other material, which will move under the influence of the electromagnetic field. At the same time, the electric current in various media will have certain features, because of what its flow in each of them will differ.
If we consider the features of the formation andflow of an electric current in metals, first of all it is necessary to pay attention to the very structure of metals, which is a crystal lattice. At the same time, ions with a positive charge are located at the nodes of this lattice, and in the space between these nodes, electrons with a negative charge move in a chaotic order. If we create an electric field around the metal, then the motion of the electrons will take a more orderly character. It can be concluded that with respect to metals, the electric current is the directed motion of electrons.
The main characteristic of the flow of electric current inmetals is a volt-ampere expression, known as Ohm's law. According to this law, the current strength is directly dependent on the voltage and in inverse relationship to the resistance. Analyzing the electric current in various media, it is necessary to give special attention to its formation and flow in a liquid medium.
Electric current in electrolytes occursdue to a reaction called electrolytic dissociation. Its essence consists in the decomposition of alkali molecules, salts or acids into positive and negative charged ions, which become carriers of the electric charge in liquids. The thing is that when an electromagnetic field starts acting on the solution, the chaotic motion of the ions turns into an ordered one. In this case, positive ions begin to move to the electrode, which has a negative charge, and negative ions to the positive charge. Thus, unlike the same metals, the electric current in the electrolytes is an ordered motion of the ions. In addition, it should be noted that during the passage of these ions through the solution on the electrodes, there is always the formation of substances that are structural components of this solution, be it alkali, acid or salt. This phenomenon, called electrolysis, is actively used in industrial plants for the production of pure metals, as well as for coating and polishing these or other products.
Considering the electric current in variousmedia, particularly in metals and liquids, we pointed out that these substances already have free ions or electrons. And what happens to the gas, which, as is known, consists of neutral molecules? Electric current without free particles with a negative or positive charge is impossible, so to begin with, the gas must be ionized, that is, create charged particles in it. The energy consumed for this will be the ionization energy, which reaches the maximum values for inert gases, and the minimum for alkali metal atoms. The ionization of the gas leads to the formation of three different types of charged particles in it - negative electrons, as well as positive and negative ions. All these particles under the influence of the external field begin to move in an orderly manner, following the same principle as for the motion of ions in liquids. Thus, the electric current in gases is the directed motion of both ions (positive and negative) and electrons.
Drawing the conclusion, we can note the following: the electric current in various environments has its own characteristics, which are widely used in various fields of the national economy, as well as in scientific research experiments.