Why is Ampere "in the electricity?"

Is the unit of current.

Scientifically, the amount of electricity passing through any section of a conductor in unit time is called current intensity, which is called current for short. Usually expressed by the letter I, its unit is ampere (André-Marie Ampère), 1775- 1836, a French physicist and chemist, who has made outstanding achievements in the research of electromagnetic action and contributed to mathematics and physics. Ampere, the international unit of current, is named after its surname. The symbol "a" also guides the directional motion of charges in the body.

The free charge in the conductor makes regular directional motion under the action of electric field force, forming current.

The electromotive force of the power supply forms a voltage, and then an electric field force is generated. Under the action of electric field force, the charges in the electric field move directionally and form current. The amount of electricity passing through 1 coulomb per second is called 1 "ampere" (a). Ampere is the basic unit of all electricity in the international system of units. In addition to A, the commonly used units are kiloamperes (kA) and milliamperes (mA), microamperes (μ a) 1A = 1 0,000 ma =10,000,000 μ a, and the directional flow direction of positive charge is electrically specified as the current direction. The microscopic expression of current in a metal conductor is I=nesv, n is the number of free charges per unit volume, e is the charge amount of electrons, s is the cross-sectional area of the conductor, and v is the charge velocity.

There are many kinds of carriers carrying charges in nature, such as movable electrons in conductors, ions in electrolytes, electrons and ions in plasma and quarks in hadrons. The movement of these carriers forms an electric current.

André-Marie Ampère (André-Marie Ampère 1775 ~ 1836), a French physicist, also contributed to mathematics and chemistry. 1775 65438+1was born in a wealthy family in Lyon on October 22nd. He showed his talent in mathematics when he was young.

Scientific achievements: 1. The most important achievement of Ampere is the study of electromagnetic action from 1820 to 1827.

(1) discovered ampere's law.

Oster's experiment of discovering the magnetic effect of current attracted Ampere's attention, which greatly impacted his long-standing belief in Coulomb's creed that electricity has nothing to do with magnetism. He concentrated all his energy on this research. Two weeks later, he presented a report on the relationship between the rotation direction of the magnetic needle and the current direction and the ruler from the right hand. Later, this law was named Ampere's Law.

(2) Discover the interaction law of current.

Then he proposed that two parallel current-carrying wires with the same current direction attract each other, and two parallel current-carrying wires with opposite current directions repel each other. The attraction and repulsion between the two coils are also discussed.

③ The galvanometer was invented.

Ampere also found that the magnetism of the current flowing in the coil was similar to that of a magnet, and made the first solenoid. On this basis, he invented a galvanometer to detect and measure current.

④ Propose the molecular flow hypothesis.

He explained the origin of geomagnetism and the magnetism of matter according to the viewpoint that magnetism is produced by moving charges. The famous molecular flow hypothesis was put forward. Ampere thinks that there is a kind of annular current-molecular current inside the molecules that make up the magnet. Because of the molecular current, each magnetic molecule becomes a small magnet, and both sides are equivalent to two magnetic poles. Usually, the molecular current orientation of magnet molecules is disordered, and the magnetic fields generated by them cancel each other, so they are not magnetic to the outside world. When the external magnetic field acts, the orientations of molecular currents are almost the same, and the adjacent currents between molecules cancel each other, but the surface parts do not cancel each other, and their effects show macroscopic magnetism. Ampere's molecular current hypothesis could not be confirmed when little was known about the material structure at that time, which contained quite a few speculative components; It has been learned today that matter is made up of molecules, and molecules are made up of atoms, in which electrons move around the nucleus. Ampere's molecular current hypothesis has real content and becomes an important basis for understanding the magnetism of matter.

⑤ Summarized the law of action between current elements-Ampere's law.

Ampere made four exquisite experiments on current interaction, summed up the law of force between current elements with superb mathematical skills, and described the relationship between the interaction between two current elements and the size, spacing and relative orientation of two current elements. Later, people called this law ampere's law. Ampere was the first to call the theory of electrodynamics "electrodynamics". 1827, Ampere integrated his research on electromagnetic phenomena into the book Mathematical Theory of Electrodynamics. This is an important classic work in the history of electromagnetism. In order to commemorate his outstanding contribution to electromagnetism, the unit of current "ampere" was named after his surname.

He also made many contributions in mathematics and chemistry. He studied probability theory and integral partial differential equations; He and David H knew the elements chlorine and iodine almost at the same time, deduced avogadro's law, demonstrated the relationship between volume and pressure at constant temperature (Boyle's law), and tried to find the classification and arrangement order of various elements.

2. Newton in Electricity

Ampere integrated his research results into the book Mathematical Theory of Electrodynamics Phenomenon, which became an important classic work in the history of electromagnetism. Maxwell praised Ampere's work as "one of the most brilliant achievements in science" and called Ampere "Newton in electricity".

Ampere was also the first person to develop the technology of measuring electricity. He made an instrument for measuring current with an automatic rotating magnetic needle, which was later improved into a galvanometer.

Ampere only worked in physics for a short time in his life, but he was able to discuss the magnetic effect of charged wires with unique and thorough analysis, so we called him a pioneer of electrodynamics, and he deserved it.