SI derived unit m), the SI derived unit of density. The names of SI derived units, when written in full, are in lowercase. However, the symbols for units named after persons are written with an uppercase initial letter. For example, the symbol for hertz is "Hz"; but the symbol for metre is "m". The International System of Units assigns special names to 22 derived units, which includes two dimensionless derived units, the radian (rad) and the steradian (sr). Some other units such as the hour, litre, tonne, bar and electronvolt are not SI units, but are widely used in conjunction with SI units.
Bubnoff unit Bubnoff unit The Bubnoff unit (abbreviated B) is a unit of speed equal to 1 m / 10 a. In other words, 1 B is equal to 1 meter in 1,000,000 years, 1 millimeter in 1,000 years, or one micrometer per year. It was defined in 1969. The Bubnoff unit is employed in geology to measure rates of lowering of earth surfaces due to erosion and is named after the Russian (German-Baltic) geologist Serge von Bubnoff (1888–1957). An erosion speed of 1 B also means that 1 m³ of earth is being removed from an area of 1 km² in