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Units and Measurements - Coggle Diagram

- - - - A unit is an internationally accepted, arbitarily chosen, reference standard for a measurement. :
        
        The International System of Units
        
        CGS System
        
        FPS System
        
        MKS System
        
        Base Units
        
        Mass - Kilograms
        Length - metres
        Temperature - Kelvin
        Current - Ampere
        Amount of substance - Mole
        Luminous Intensity - candela
        
        Large scale measurements
        
        Length
        
        1 A.U = 1.496 X 10^11m, 1 light year = 9.46 X 10^15, 1 parsec = 3.08 X 10^16 m
        
        Mass
        
        1 solar mass = 10^30kg
        
        Small Scale measurements
        
        Length
        
        1 fermi = 10^15 m
        
        1 Angstrom = 10^-10 m
        
        Mass
        
        Unified atomic mass unit (u) = 1.66 X 10^-27 kg
- - - - Systematic errors
      - Random errors
  - - - The magnitude of differences between the individual measurements and the true value of the quantity is called the absolute error of measurement
    - - It is the ratio of the mean absolute error to the mean value of the quantity measured
    - - When the relative error is expressed in per cent, it is called the percentage error