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pion

(Encyclopedia)pion pīˈŏn [key] or pi meson, lightest of the meson family of elementary particles. The existence of the pion was predicted in 1935 by Hideki Yukawa, who theorized that it was responsible for the f...

charge

(Encyclopedia)charge, property of matter that gives rise to all electrical phenomena (see electricity). The basic unit of charge, usually denoted by e, is that on the proton or the electron; that on the proton is d...

magnetic resonance

(Encyclopedia)magnetic resonance, in physics and chemistry, phenomenon produced by simultaneously applying a steady magnetic field and electromagnetic radiation (usually radio waves) to a sample of atoms and then a...

Rancho Cordova

(Encyclopedia)Rancho Cordova rănˈchō kôrdōˈvə [key], uninc. residential city (1990 pop. 48,731), Sacramento co., N Calif. A suburb of Sacramento, it experienced rapid growth in the late 20th cent. Nursery pr...

Millikan, Robert Andrews

(Encyclopedia)Millikan, Robert Andrews mĭlˈĭkən [key], 1868–1953, American physicist and educator, b. Morrison, Ill., grad. Oberlin College, 1891, Ph.D. Columbia, 1895, studied in Germany. He taught (1896–1...

thermionic emission

(Encyclopedia)thermionic emission thûrmˌīŏnˈĭk [key], emission of electrons or ions by substances that are highly heated, the charged particles being called thermions. The number of thermions emitted increase...

Hansen, William Webster

(Encyclopedia)Hansen, William Webster, 1909–49, U.S. physicist, b. Fresno, Calif. Hansen received his doctorate in physics from Stanford in 1933 and joined the faculty there in 1934. He invented the high-quality ...

Hall effect

(Encyclopedia)Hall effect, experiment that shows the sign of the charge carriers in a conductor. In 1879 E. H. Hall discovered that when he placed a metal strip carrying a current in a magnetic field, a voltage dif...

magnetron

(Encyclopedia)magnetron măgˈnĭtrŏnˌ [key], vacuum tube oscillator (see electron tube) that generates high-power electromagnetic signals in the microwave frequency range. Its operation is based on the combined ...

cathode-ray tube

(Encyclopedia)CE5 Cathode-ray tube cathode-ray tube (CRT), special-purpose electron tube in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected towar...