Candela (unit of luminous intensity; Symbol cd), defined as the intensity in a given direction of a source emitting radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian;
Mole (unit of amount of substance; Symbol mol), defined as containing as many elementary entities of a substance as there are atoms in 0.012 kilogram of carbon-12;
Kelvin (unit of temperature; Symbol K) which is 1/273.16 of the thermodynamic temperature of the triple point (equilibrium among the solid, liquid, and gaseous phases) of pure water.
Other scientific measures are given below :
Angstrom: Unit of wavelength of light is Angstrom. 1 Angstrom = 10-8 cm. There is a bigger unit for measuring the wavelength of infrared light; it is called a millimicron and is equal to 10-7 cm. Micron = 10″4 cm, is a still bigger unit.
Atomic Weight: The weight of an atom of hydrogen is taken as the standard; the respective weights of the atoms of all other substances are expressed in terms of it. So when it is stated that the atomic weight of iron is 56, it is meant that the atom of iron is 56 times as heavy as the atom of hydrogen.