# Tag Info

## New answers tagged metrology

2

This is a fairly subjective question. I do not think there is a need for such a constant. Why? First, lets look at... The definition of the mole Taken from Wikipedia: ... is defined as the amount of a chemical substance that contains as many elementary entities, e.g., atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of ...

0

The speed of light is invariable but the number or ratio of the frames of reference are variable as determined by the amount of gravity, the result of which is gravitational lensing.

3

The BIPM (Bureau International de Poids et Mesures) defines the meter as the distance traveled by light in $\frac{1}{299792458}$ seconds. The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. The speed of light as $299792458$ m/s is therefore exact and not a measured value. Similarily, ...

5

This is an exact value. Meter is defined by the speed of light. Meter is a distance that the light travels during $\frac{1}{299792458}$ of a second.

2

Calibration is pretty easy: take an isothermal environment and measure two events with known physical effects: an ice-water bath and boiling point of water. Define your thermometer to read those well defined values at these well defined temperatures and, assuming your thermometer has a roughly linear scaling, you have just calibrated your thermometer. Its ...

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