Washington: Scientists have made the most precise determination yet of the Planck’s constant – an important value in science that will help redefine kilogram, the official unit of mass in the international system of units. To measure Planck’s constant, NIST uses an instrument known as the Kibble balance, which uses electromagnetic forces to balance a kilogram mass. In one mode, an electrical current goes through the coil, generating a magnetic field that interacts with the permanent magnetic field and creates an upward force to balance the kilogram mass. This upward motion induces a voltage in the coil that is proportional to the strength of the magnetic field. The researchers also tested for variations in the magnetic field during both modes of operation and discovered they had been overestimating the impact the coil’s magnetic field was having on the permanent magnetic field.

Source: Mint July 03, 2017 12:45 UTC