Measurements, quantities and units

Units of physical quantities, particular physical quantities to which, by definition, numerical values equal to unity are assigned.

Natural systems of units , systems in which the base units are fundamental physical constants, such as the gravitational constant G, the speed of light in vacuum c, the Planck constant h, the Boltzmann constant k, the Av…

Measurement , a sequence of experimental and computational operations carried out in order to find the value of a physical quantity that characterises some object or phenomenon.

Measuring system , an item of measuring equipment which in the general case is a set of measuring instruments, measuring transducers, material measures, measurement switches, communication lines and digital and analogue …

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.

(from the French calibre — magnitude, size, template).

(Jy), a non-SI unit of the spectral flux density of radiation, used in radio astronomy.

(from the Latin justus — correct), the set of operations that bring measuring instruments into a state ensuring their correct functioning.

A sequence of values assigned by convention to a physical quantity as it increases (or decreases).

Methods of measuring colour and expressing it quantitatively.

(L), a non-SI unit of luminance (usually of the luminance of a surface that scatters light), used mainly in the USA.

An obsolete unit of frequency interval. Named after the French physicist F.

(from the Greek nanos - dwarf), a prefix attached to the name of a unit of a physical quantity to form the name of a submultiple unit equal to 10 -9 of the original unit.

On this page you can download useful programs for physics, with the help of which various calculations are easier to carry out.