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Equation 3 · Part 7 · The Last Artefact: Redefining the Kilogram

subscript

mxgv=I1U2m_x g v = I_1 U_2
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

The geometric factor Bl appears in both and is eliminated between them: mxgv=I1U2m_x g v = I_1 U_2. The BIPM’s mise en pratique is careful about what has just happened: “power of a mechanical nature is equated to power of an electromagnetic nature. The powers are manifestly ‘virtual’ in this method of operation because power does not figure in either mode of this two-mode experiment” [ 4 ] . No power is transferred in either measurement. The equality is between quantities constructed after the fact.

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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.

Open the illustrated subscripts: which member of a family? guide →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.