Equation 2 · Part 3 · The Last Artefact: Redefining the Kilogram

Symbol I_1

m_x g = I_1 B l \qquad\text{and}\qquad U_2 = v B l

I_1

What this part means

$I_1$ is an input to the expression that computes the quantity on the left.

Its job in the formula

$I_1$ is an input to the expression that computes the quantity on the left.

Full expressionSymbol I_1Article meaning

The passage around this formula

The Kibble balance runs in two modes. In weighing mode, the weight of an artefact of mass m is balanced by the force on a coil of wire length l carrying current I₁ in a radial field of flux density B. In moving mode, the same coil is driven vertically at velocity v through the same field and the induced voltage U₂ is measured [ 4 ] : $m_x g = I_1 B l \qquad\text{and}\qquad U_2 = v B l$ . The geometric factor Bl appears in both and is eliminated between them:

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the surrounding passage

[4] Mise en pratique for the definition of the kilogram in the SI ↗

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