FAQs
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Random FAQs
- 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.
- No, the difference is not very meaningful at all.
- The 10% rule says that if a component tolerance is given as x then the instrument used to demonstrate compliance should have an uncertainty of better than x/10.
- There are several reasons for maintaining separate national capabilities.
- Calibration is the process of comparing a measuring instrument with a measurement standard to establish the relationship between the values indicated by the instrument and those of the standard.
- To convert one non-pascal pressure unit to an alternative non-pascal unit, multiply the 'starting' pressure value by the 'number of pascals' shown against its unit and then divide the product by the number of pascals shown against the second unit.
- The mass of a body relates to the amount of material it contains and there is no difference between mass and true mass. When a weight is calibrated the mass value quoted on its certificate of calibration is normally a conventional mass value - appropriate where the value is determined by weighing the item in air.
- What is evolving is our knowledge of the constants not as far as we know their values, which for the purposes of evaluation are considered constant.
- An internet search should lead you to companies which sell such items.
All FAQs
- Yes, magnetic fields - and indeed magnetically permeable materials close to a balance - can effect a weighing result.
- Check plugs and parametric measurements are not mutually exclusive. It is NPL's opinion that for checking master gauges (i.e. not products) both check plugs and parametric measurements have their place.
- The Rugby radio station, with call-sign GBR, was brought into service in 1926 by the Post Office as a telegraphy station with world-wide coverage and a frequency of 16 kHz.
- Historically there have been a variety of units of mass and density, and approximate conversion factors to some of these are given below.
- The answers to some frequently asked questions about length metrology.
- To some degree yes. Ideally, the reflectivity of both the reference and test surface should be equal to give maximum contrast fringes.
- There are many good books and in addition NPL produces a range of Good Practice Guides relating to dimensional metrology.