feet; abbreviation: ft; symbol: â² , the prime symbol) is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly. In both systems, the foot comprises 12 inches and three feet compose a yard.
Avogadro's law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) is an experimental gas law relating volume of a gas to the amount of substance of gas present.[1] A modern statement of Avogadro's law is:
Avogadro's number was defined by Perrin as the number of molecules in one gram-molecule of hydrogen. It was later redefined as the number of atoms in 12g of the isotope carbon-12. Thus, Avogadro's number is a dimensionless quantity and has the numerical value of the Avogadro constant given in base units. see more Â».