Radioactivity of a substance in which one atom disintegrates per second.
degree Celsius
Division into 100 parts of the difference between the freezing point of water (0°C) and its boiling point (100°C) at standard atmospheric pressure.
pascal
Uniform pressure exerted on a flat surface of 1 m2 with a force of 1 newton.
mole
Quantity of matter equal to the number of atoms in 0.012 kg of carbon 12.
newton
Force required to impart an acceleration of 1 m/s2 to a body having a mass of 1 kg.
kelvin
Zero degrees Kelvin is equal to minus 273.16°C.
kilogram
Mass of a platinum prototype that was accepted as the international reference in 1889; it is stored at the International Bureau of Weights and Measures.
meter
Distance traveled by light in a vacuum in 1/299,792,458 of a second.
