pass an electric current
61technology, history of — Introduction the development over time of systematic techniques for making and doing things. The term technology, a combination of the Greek technē, “art, craft,” with logos, “word, speech,” meant in Greece a discourse on the arts, both… …
62X-ray — [ 22 December 1895 and presented to Professor Ludwig Zehnder of the Physik Institut, University of Freiburg, on 1 January 1896. The dark oval on the third finger is a shadow produced by her ring. [cite book last = Kevles first =Bettyann Holtzmann …
63Fluorescent lamp — A fluorescent lamp or fluorescent tube is a gas discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light.Unlike… …
64Wardenclyffe Tower — (1901 ndash; 1917) also known as the Tesla Tower, was an early wireless telecommunications aerial tower designed by Nikola Tesla and intended for commercial trans Atlantic wireless telephony, broadcasting, and to demonstrate the transmission of… …
65bioelectricity — bi·o·e·lec·tric·i·ty (bī ō ĭ lĕk trĭsʹĭ tē, ē lĕk ) n. An electric current that is generated by living tissue, such as nerve and muscle. * * * ▪ biology electric potentials and currents produced by or occurring within living organisms.… …
66electronics — /i lek tron iks, ee lek /, n. (used with a sing. v.) the science dealing with the development and application of devices and systems involving the flow of electrons in a vacuum, in gaseous media, and in semiconductors. [1905 10; see ELECTRONIC,… …
67Mathematical descriptions of physical laws — For worded descriptions and criteria of physical laws, see Physical law. For the nomenclature used see Physical quantity and Defining equation (physics). Physical laws are often summarized by a single equation, or at least a small set of… …
68Switch — For other uses, see Switch (disambiguation). Electrical switches. Top, left to right: circuit breaker, mercury switch, wafer switch, DIP switch, surface mount switch, reed switch. Bottom, left to right: wall switch (U.S. style), miniature toggle… …
69Membrane potential — Differences in concentration of ions on opposite sides of a cellular membrane lead to a voltage called the membrane potential. Many ions have a concentration gradient across the membrane, including potassium (K+), which is at a high inside and a… …
70Crookes tube — A Crookes tube. The electrons travel in straight lines from the cathode on the left, shown by the shadow cast by the cross on the fluorescence on the righthand wall. The anode is at the bottom. A Crookes tube is an early experimental electrical… …
