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My short answer comes from reading this page on the web: https://www.4physics.com/phy_demo/at_clock/at_clock.htm For more details, please go to that page. It is very clear. The Cesium atom itself is not oscillating. The oscillation being measured is the frequency of the photon that is emitted by the Cesium valence electron when it jumps from an excited ...


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So the BIPM has now released drafts for the mises en pratique of the new SI units, and it's rather more clear what the deal is. The drafts are in the New SI page at the BIPM, under the draft documents tab. These are drafts and they are liable to change until the new definitions are finalized at some point in 2018. At the present stage the mises en pratique ...


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The point is that luminous intensity is intensity as perceived by the human eye, and particularly taking into account the fact that the same amount of power will be perceived as brighter or dimmer depending on whether the wavelength is at a maximum of the eye's sensibility or at a minimum. This makes the candela ever so slightly washier than the other six ...


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Personally, from a pure physics point of view, i don't think we need the candela as a base S.I. unit. it seems that all we need is: m,kg,s,A,K,mol These can all be related to basic physics constants (see Physics Today, July 2014, p. 37): c,h,delta nu(pick any atomic transition),e,k(Boltzmann),N_A(Avogadro's) Actually, even N_A is only necessary from a ...



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