Physical World and Measurement

Amount of subtance containing the same number of particles as there are atoms in 0.012 kg of carbon 12

Source which emits radiation of frequency 540 x 10² Hz with radiant intensity of 1/683 watt per steradian

Current between two straight parallel conductors separated 1m apart which generates 2 x 10⁻⁷ N/m

1 / 273.16 of thermodynamic temperature at triple point of water

9.2 Billion vibrations of transition between two level of cesium-133 atom in ground state

Mass of platinum iridium cylinder kept in International Bureau of weights in paris, France

1.65Million wavelength of orange red coloured radation emitted by krypton 86

Relative error expressed in percentage

Ratio of error observed in the measurement to the actual value

Difference in actual value and the measured value