Kilogram Proposed redefinition of SI base units

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a watt balance being used measure planck constant in terms of international prototype kilogram.


the definition of kilogram undergoing fundamental change—the current definition defines kilogram being mass of international prototype kilogram artefact, not constant of nature while new definition relates equivalent energy of photon via planck constant.



current definition: kilogram unit of mass; equal mass of international prototype of kilogram.


proposed definition: kilogram, symbol kg, si unit of mass. defined taking fixed numerical value of planck constant h 6966662607015000000♠6.62607015×10 when expressed in unit j⋅s, equal kg⋅m⋅s, metre , second defined in terms of c , Δνcs.

one consequence of change new definition makes definition of kilogram dependent on definitions of second , metre.





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