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radioactivity

(Encyclopedia)CE5 Effects of a magnetic field on the products of radioactivity CE5 Disintegration series: Radioactive decay of radium-226 into lead-206 radioactivity, spontaneous disintegration or decay of t...

nuclear energy

(Encyclopedia)CE5 Graph of binding energy per nucleon as a function of mass number nuclear energy, the energy stored in the nucleus of an atom and released through fission, fusion, or radioactivity. In these pr...

Mach, Ernst

(Encyclopedia)Mach, Ernst ĕrnst mäkh [key], 1838–1916, Austrian physicist and philosopher, b. Moravia. He taught (1864–67) mathematics at Graz and later, until his retirement in 1901, was professor of physics...

luminosity

(Encyclopedia)luminosity, in astronomy, the rate at which energy of all types is radiated by an object in all directions. A star's luminosity depends on its size and its temperature, varying as the square of the ra...

Griffenfeld, Peder Schumacher, Count

(Encyclopedia)Griffenfeld, Peder Schumacher, Count pāˈᵺər sho͞oˈmäkhər, grĭfˈənfĕlt [key], 1635–99, Danish politician. The son of a merchant, he became (1665) secretary to Frederick III. In 1665 Grif...

Fortescue, Sir John

(Encyclopedia)Fortescue, Sir John fôrˈtĭskyo͞o [key], c.1394–1476, English jurist. A supporter of the Lancastrian king Henry VI, he was chief justice of the Court of King's Bench from 1442 until 1461, when He...

Iguala

(Encyclopedia)Iguala ᵺā lä ēnˌdāpĕndĕnˈsyä [key], city, Guerrero state, S Mexico, on the...

Feuerbach, Ludwig Andreas

(Encyclopedia)Feuerbach, Ludwig Andreas foiˈərbäkh [key], 1804–72, German philosopher, educated at Heidelberg and Berlin; son of Paul Johann Anselm von Feuerbach. At first a Hegelian, he abandoned absolute id...

substance

(Encyclopedia)substance, in philosophy, term used to denote the changeless substratum presumed in some philosophies to be present in all being. Aristotle defined substance as that which possesses attributes but is ...

atomic mass

(Encyclopedia)atomic mass, the mass of a single atom, usually expressed in atomic mass units (amu). Most of the mass of an atom is concentrated in the protons and neutrons contained in the nucleus. Each proton or n...