FAQs
FAQs Areas
Random FAQs
- SI units are divided into two classes, base units and derived units. The base units are dimensionally independent.
- Radiation thermometers measure the thermal energy emitted by a source and relate this to its temperature by means of the Planck law of radiation. They consist of optics (generally lenses) to collect and focus the emitted energy onto a detector.
- Yes it can in some circumstances but, where it does, it is fairly easy to ensure that its effect on the measurement uncertainties obtained is negligible.
- In 1799 it was agreed that the unit should be the mass of one cubic decimetre of water at a temperature of 4 °C, which would be called a kilogram (kg). The mass of one cubic centimetre of water would be called a gram (g).
- There are a few possible answers...
- The MSF time signal provides a good service throughout the British Isles, with signal strengths greater than 100 µV/m at 1000 km from Anthorn (in Cumbria) in all directions.
- Instrument calibration is often thought to be expensive but the information contained in the resultant certificate is usually worth considerably more. This is not always appreciated and, on receipt, many certificates are wastefully consigned to drawers, shelves or even wall plaques.
- Flyers are available for download or you can contact us.
- No, they are not. The internationally recognised SI unit for pressure is the pascal, abbreviated to Pa, and this is the unit realised by the primary measurement standards in the world's national metrology institutes to provide traceability for pressure measurements.
- The answer to this question depends on the type of barometer in question, particularly whether its pressure sensing mechanism is influenced by gravity or not, and what you are trying to get it to measure.
All FAQs
- Accurate measurement of thermal conductivity is not quite as straightforward as the simple steady-state theory would suggest.
- These can be downloaded...
- A flyer is available for download or you can contact us.
- The answer to this question depends on the type of barometer in question, particularly whether its pressure sensing mechanism is influenced by gravity or not, and what you are trying to get it to measure.
- There are commercial organisations that are accredited for this purpose.
- An air buoyancy correction has to be made, where the measurement uncertainty required of a weighing warrants it, when the volumes (and hence the amount of displaced air) of two masses being compared are different.
- Pressure in a fluid, whether it be gas or liquid, varies with height. It doesn't matter whether the fluid is in pipework or more loosely confined such the atmosphere or the sea - just so long as there is gravitational attraction and something stopping free-fall (or a centripetal force - for those who are pedantic, in orbit or who twirl open cups of tea on horizontal cords).