# Category «General terms»

## Permanent magnet

A permanent magnet is an object that retains its magnetization for a long period of time. A magnetic field exists around a magnetized object. This magnetic field exerts a magnetic force on another magnetized object. The locations on a magnet with the greatest magnetic effect are called the magnet’s poles. Each magnet has two poles: …

## Magnetic flux

Magnetic flux – is the flow of the magnetic induction vector through a certain surface. (symbol Φ) In the SI system, the unit of magnetic flux is the weber (1 Wb = 1 V·s = 1 T·m² = 1 J/A = 108 maxwells in the CGS system – maxwell (1 Mx = 1 Gs·cm² = …

## Electric field

Electric field is a special form of matter that exists around charged objects or particles and exerts a certain force on other particles or bodies with electric charge.

## Voltage

In every closed electrical circuit, current performs work, and the amount of work depends on the strength of the current. The greater the current, the more work it does. However, there is another quantity that affects the work, and it is called electric voltage or simply voltage.

## Electroscope

An electroscope is a device used to detect electric charges, which can detect whether an object is electrically charged and estimate the magnitude of the electric charge.

## Electromagnet

An electromagnet is a coil with a ferromagnetic core inserted into it. The magnetic field of a current-carrying coil is of particular practical interest. If a coil with current is suspended on thin and flexible wires, it will align itself just like a compass needle: one end will point north, and the other end will …

## Electric charge

Electric charge is a physical quantity that characterizes the property of objects or particles to interact electromagnetically and determines the magnitude of forces and energies during such interactions.

## Coulomb’s Law

Coulomb’s law states that the force between two charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. Mathematically, this can be expressed as:

## Ohm’s Law

Ohm’s Law This law takes into account the key quantitative characteristics of an electric circuit: Ohm’s Law А law stating that electric current is proportional to voltage and inversely proportional to resistance. To describe an electric circuit that does not contain EMF, you can use Ohm’s law for a section of the circuit. This is …

## Semiconductor

A semiconductor is a substance that occupies an intermediate position between conductors, which have high electrical conductivity (metals, electrolytes), and dielectrics, which conduct almost no electric current (porcelain, rubber, and others).