Equation 1 · Part 6 · From Origins to Frontier: A History of Scientific Instruments and Metrology
=
=
What this part means
The expressions on both sides represent the same quantity under the stated assumptions.
Its job in the formula
The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.
Full expression→=→Article meaning
The passage around this formula
Because voltage and resistance can themselves be measured to extraordinary precision using quantum electrical effects (the Josephson effect and the quantum Hall effect), a Kibble balance effectively measures mass in terms of the Planck constant, h. The relationship, in its simplified form, is: . where m is the test mass, g the local gravitational acceleration (independently and precisely measured at the balance’s location), v the coil’s velocity in the moving phase, and U and I the voltage and current measured electrically. Combined with the quantum electrical measurements of U and I in terms of h , this equation is what let NIST’s NIST-4 Kibble balance measure the Planck…
Learn the underlying idea
An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.
Open the illustrated equality: what the equals sign claims guide →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.