Table of contents  
Measurement  
Unit  
The Seven Base Units Of Measurement  
Derived Units  
The International System of Units  
Units of Long Distance  
Units of Short Distance  
Mass & Weight 
Measurement is a technique in which the properties of an object are determined by comparing them to a standard.
A unit is a particular physical quantity, defined and adopted by the convention, with which other particular quantities of the same kind are compared to express their value.
The units of measurement derived from the seven base units specified by the International System of Units is known as SI derived units.
Name  Symbol  Quantity 
hertz  Hz  Frequency 
radian  rad  angle 
newton  N  force, weight 
farad  F  electrical capacitance 
ohm  Ω  electrical resistance, impedance, reactance 
weber  Wb  magnetic flux 
degree Celsius  °C  temperature relative to 273.15 K 
becquerel  Bq  radioactivity (decays per unit time) 
In earlier times scientists of different countries were using different systems of units for measurement.
• In CGS system they were centimeter, gram, and second respectively.
• In FPS system they were foot, pound, and second respectively.
• In MKS system they were meter, kilogram, and second respectively.
Base Quantity  Name  Symbol 
length  meter  m 
mass  kilogram  kg 
time  second  s 
electric current  ampere  A 
temperature  kelvin  K 
amount of substance  mole  mol 
luminous intensity  candela  cd 
Name  deca  hecto  kilo  mega  giga  tera  peta  exa  zetta  yotta 
Prefix  da  h  k  M  G  T  P  E  Z  Y 
Factor  10^{1}  10^{2}  10^{3}  10^{6}  10^{9}  10^{12}  10^{15}  10^{18}  10^{21}  10^{24} 
Name  deca  hecto  kilo  mega  giga  tera  peta  exa  zetta  yotta 
Prefix  da  h  k  M  G  T  P  E  Z  Y 
Factor  10^{1}  10^{2}  10^{3}  10^{6}  10^{9}  10^{12}  10^{15}  10^{18}  10^{21}  10^{24} 
Name  deci  centi  milli  micro  nano  pico  femto  atto  zepto  yocto 
Prefix  d  c  m  μ  n  p  f  a  z  y 
Factor  10^{−1}  10^{−2}  10^{−3}  10^{−6}  10^{−9}  10^{−12}  10^{−15}  10^{−18}  10^{−21}  10^{−24} 
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