Measured quantity

According to DIN 1319 to the "Fundamentals of Metrology " is the measure of that physical quantity, which is considered a measurement. Here in this Standard, the term is used for both " measure in a general sense " as well as " special measure ".

  • In a general sense, it is a physical quantity such as mass, power, temperature, the target of a measurement was or will be. Limitation: For example, since the intelligence quotient is not a physical size, it may not be a measurable quantity within the meaning of this definition.
  • As a special size is associated with a specific non-cash benefits such as volume size of a body submitted, resistance of a copper wire presented at a given temperature. The of a measuring instrument or a measuring device delivered or to be delivered value of a particular measure is called the measured value; it is expressed by the product of numerical value and unit. Definition: For the purposes of this definition are the values ​​that were obtained, eg, by mere reasoning or conjecture, not to designate as measured values ​​.

The measure must not be directly addressed by the measurement. It can also be determined by physically known or fixed mathematical relationships of variables, which are direct measurements. Goal of any measurement is to determine the true value of the measurand. It is possible, at best, be indicated by a complete measurement result an estimate.

The measure will often be property of a body; it can (for example, radiation ), or a state (such as an electric field ) may also be characteristic of a process.

A distinction is made dimensionless variables ( for example, angle, refractive index, eccentricity of the orbit of a satellite, etc.), their values ​​can be obtained directly as a rational number, and dimension lossy variables ( e.g. duration, charge density), the values ​​of which in each case to be compared with values ​​of the same dimension. This comparison is expressed by specifying that the value of a dimensionful measure as a multiple of the associated unit. In practice, the clarity can be used for many units ( auxiliary units) also dimensionless.

In the field of quantum physics, certain measures are to each other, and the same system is complementary, ie, causes the measurement of a size that the value of the other variable is completely undetermined (see quantum mechanics or observable ).

Swell

  • Metrology
  • Measure
Electric power Charge (physics)
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