state and explain the units chosen as fundamental units in the SI system
Answers
Explanation:
Within SI there are seven base units upon which all others are based. The base units include: mass, length, time, temperature, amount of substance, electric current, and luminous intensity.
Metre: The metre is the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 second.
Kilogram: The kilogram is the unit of mass equal to the mass of the international prototype of kilogram.
Second: The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levers (F=4, mF=0 to F=3, mF=0) of the ground state of the cesium 133 atom.
Ampere: The ampere is the constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2x10-7 Newton per meter of length.
Kelvin: The Kelvin, unit of thermodynamic temperature is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
Mole: The mole is the mount of substance of a system which contains as many elementary entities as there are atoms in .012 kg of carbon 12 (about 6.022x1023 atoms). When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
Candela: The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540x1012 Hz and that has a radiant intensity in that direction of 1/683 watt per steradian.
These are the SI base units. Every other SI measurement is derived from some algebraic combination of these units.
