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Equation 4 · Part 3 · The Last Artefact: Redefining the Kilogram

Symbol h

KJ=2eh,RK=he2,KJ2RK=4hK_{\mathrm J} = \frac{2e}{h}, \qquad R_{\mathrm K} = \frac{h}{e^{2}}, \qquad K_{\mathrm J}^{2} R_{\mathrm K} = \frac{4}{h}
hh

What this part means

the fixing.

Its job in the formula

h is an input to the expression that computes the quantity on the left.

Where the article explains it

Fixing h and e together dissolved the parallel system: KJ and RK are now calculated exactly from the defining constants, and the conventional values were retired [ 3 ] .

The passage around this formula

…a stable resistor; both voltages are measured against the Josephson constant, taken as KJ = 2e/h, and the resistance against the von Klitzing constant, taken as RK = h/e², so that KJ²RK = 4/h and the mass reduces to h multiplied by an experimental frequency term and divided by the product of local gravity and coil velocity [ 4 ] : KJ=2eh,RK=he2,KJ2RK=4hK_{\mathrm J} = \frac{2e}{h}, \qquad R_{\mathrm K} = \frac{h}{e^{2}}, \qquad K_{\mathrm J}^{2} R_{\mathrm K} = \frac{4}{h}. This is where the quantum electrical standards earn their place. Since 1990 the practical realization of the volt and the ohm had rested on the Josephson and…

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A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

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