FAQs
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Random FAQs
- The MSF radio signal has a very long wavelength (5 km) which is comparible or larger than dimensions of the metalwork of buildings and pylons which act as a screening mesh and greatly reduce the signal strength.
- The complete inspection by direct measurement of parallel screw threads necessitates the measurement of the effective diameter which, in the case of external threads, is obtained by measurement across cylinders placed in the threads on either side of the screw.
- Yes, the Measurement of Surface Texture using Stylus Instruments, Guide No 37.
- This is used for the coating on radiometers because, when applied in the appropriate manner, it is one of the lowest reflectance surfaces that exist.
- Calibrated Gas Mixtures (CGMs) are lower down in the gases hierarchy than PRGM or SGS.
- The triple point temperature of a pure substance is the unique temperature at which the solid, liquid and vapour phases of the substance co-exist in thermal equilibrium. Such triple points make ideal reference points for the calibration of thermometers.
- The methods used to determine values of air density fall into two broad categories – indirect (that is calculation from measurement of other parameters and known as the parametric method) and direct measurement. The parametric method is used more commonly.
- Thermocouples are the most common sensors in industrial use due to the fact that they are small, simple, rugged and of low cost. They consist of two dissimilar conductors (wires) joined at a junction and contained in an insulator.
- The solid-state 60 kHz transmitter at Anthorn typically operates at around 27 kW of radio-frequency signal which gives an equivalent monopole radiated power of approximately 17 kW.
All FAQs
- 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 International Prototype Kilogram is not perfectly stable (its mass changes with time), the amount it changes cannot be known perfectly (there is no 'perfect' reference against which to judge it) and the values of the national copies cannot be monitored at the highest level of accuracy without being compared directly with it.
- In some situations.
- The most accurate barometers are indeed the mercury primary barometers used at national measurement institutes. Most barometers, though, are secondary instruments rather than primary ones and when considering these it is not correct to say that those based on a mercury column are invariably more accurate than those that are based on an alternative principle.
- Yes there are - some are listed here.
- The time at which summer time begins and ends is given in the relevant EU Directive and UK Statutory Instrument as 1 a.m. Greenwich Mean Time (GMT).
- Up to a point yes, but unless a weight is of suitable design and material and in appropriate condition it will not be possible to give it a meaningful calibration and it would certainly be a waste of money.
- Give the weight a general inspection to check its construction, surface finish and the suitability of its magnetic properties.
- A number of factors need to be taken into account when considering sources for calibrating radiation thermometers.
- Yes - Saturated (or unsaturated) salt solutions, and certain other chemicals, can be used to generate an environment of a particular relative humidity in an enclosed space.