International Definitions of Fundamental Units Physics Notes
International Definitions of Fundamental Units:
1. Metre: 1 meter is defined as the distance travelled by light in vacuum in \(\frac{1}{299792458}\) of a second.
2. Kilogram: General Conference of Weights and Measures (GCWM) defined kilogram as the mass of Platinum Irridium cylinder kept at the Bureau of Weight and Measures at Sevres near Paris, France.
3. Second: One second is equal to the duration of 9,192,631,770 vibrations corresponding the transition between two hyperfine levels of Caesium 133 atom in the ground state.
4. Ampere: 1 ampere is the constant current which when maintained in each of the two straight parallel current-carrying conductors of infinite length of negligible area of cross-section and held one metre apart in vacuum produce a force of 2 × 107 Nm between them.
5. Kelvin: 1 Kelvin is the fraction \(\frac{1}{273.16}\) of the thermodynamical temperature of the triple point of water.
6. Candela: One candela is that luminous intensity in a perpendicular direction of \(\frac{1}{600000}\) m2 area of a black body at the freezing point of Platinum under a pressure of 101. 325 N m-2.
7. Mole: One mole is that amount of substance that contains as many elementary entities as there are atoms in 0.012 kg of pure 6C12.
8. The Kelvin unit of thermodynamic temperature is the fraction \(\frac{1}{273.16}\) of the thermodynamic temperature of the triple point of water.