Electricity and magnetism

Unified field theory , a unified theory of matter, intended to reduce the variety of the properties of elementary particles and of the laws of their mutual transformation (interaction) to a few universal principles.

Measuring instrument , an item of measuring equipment that makes it possible to read off the value of the measured quantity directly.

Measuring amplifier , a device for amplifying electrical signals (current, voltage) and also for converting voltage into current and the other way round.

Kapitza's law , an empirical rule according to which the electrical resistance of polycrystalline samples of metals in a strong magnetic field grows in proportion to the magnetic field strength.

Cathode , (from the Greek kathodes — a way down, a return; the term was proposed by the English physicist M.

Cathode fall of potential, the potential difference between the cathode of an electric discharge in a gas and the plasma column.

Cathode spot , a brightly glowing spot on the surface of the cathode.

Cathode rays , a flow of electrons in a glow discharge at so low a pressure that a considerable part of the electrons, accelerated in the region of the cathode dark space, cross practically the whole of the discharge gap…

Quadrupole interaction , the interaction of systems of charged particles that is due to these systems having a quadrupole moment (see Quadrupole ).

1) a particular form of interaction between electric currents, between currents and magnets (that is, bodies with a magnetic moment) and between magnets; 2) the branch of physics that studies this interaction and the pro…

The constant of proportionality μ 0, which appears in a number of the formulae of electromagnetism when they are written in the International System of Units (SI).

Mesons , unstable elementary particles belonging to the class of hadrons; unlike baryons, mesons carry no baryon charge and have zero or integer spin (they are bosons).

Meissner effect , the complete expulsion of a magnetic field from a metallic conductor when the latter becomes superconducting (as the temperature and the magnetic field strength fall below the critical value H k ).

Nuclear photographic emulsion - a photographic emulsion for recording the trajectories (tracks) of charged particles.

A surface all of whose points have one and the same potential.

Electric field , a particular form in which the electromagnetic field manifests itself (alongside the magnetic field), and which determines the force exerted by the field on an electric charge, a force that does not depe…

An antenna in the form of a slot in a metal screen.

An electrical discharge in a gas in which the electrons that arise on ionisation themselves produce further ionisation.

Left-hand rule , for finding the direction of the mechanical force that acts on a current-carrying conductor in a magnetic field: if the left palm is held so that the outstretched fingers coincide with the direction of t…

An electric current in a gas that requires no action of an external ioniser to sustain it.