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The curie (symbol Ci) is a non- SI unit of radioactivity originally defined in 1910. According to a notice in Nature at the time, it was to be named in honour of Pierre Curie, [1] but was considered at least by some to be in honour of Marie Curie as well, [2] and is in later literature considered to be named for both. [3]
Definition. The dyne is defined as "the force required to accelerate a mass of one gram at a rate of one centimetre per second squared". [ 2] An equivalent definition of the dyne is "that force which, acting for one second, will produce a change of velocity of one centimetre per second in a mass of one gram". [ 3]
The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for amount of substance, a quantity proportional to the number of elementary entities of a substance. One mole contains exactly 6.022 140 76 × 1023 elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can ...
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million ( ppm ...
Avogadro constant. The Avogadro constant, commonly denoted NA[ 1] or L, [ 2] is an SI defining constant with an exact value of 6.022 140 76 × 1023 mol−1 ( reciprocal moles ). [ 3][ 4] It is defined as the number of constituent particles (usually molecules, atoms, or ions) per mole ( SI unit) and used as a normalization factor in the amount ...
The gram (originally gramme; [1] SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one thousandth of a kilogram.. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre [1 cm 3], and at the temperature of melting ice", [2] the defining temperature (≈0 °C) was later changed to 4 ...
The rad is a unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg. [ 1] It was originally defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by one gram of matter. The material absorbing the radiation can be human tissue, air, water, or any other substance.
4.184 J. The calorie is a unit of energy that originated from the caloric theory of heat. [1] [2] The large calorie, food calorie, dietary calorie, or kilogram calorie is defined as the amount of heat needed to raise the temperature of one liter of water by one degree Celsius (or one kelvin ). [1] [3] The small calorie or gram calorie is ...