low-frequency energy
81radio — /ray dee oh /, n., pl. radios, adj., v., radioed, radioing. n. 1. wireless telegraphy or telephony: speeches broadcast by radio. 2. an apparatus for receiving or transmitting radio broadcasts. 3. a message transmitted by radio. adj. 4. pertaining …
82Photoelectric effect — The photoelectric effect is a quantum electronic phenomenon in which electrons are emitted from matter after the absorption of energy from electromagnetic radiation such as x rays or visible light.cite book | title = Physics for Scientists… …
83Antenna (radio) — Whip antenna on car …
84sound — sound1 soundable, adj. /sownd/, n. 1. the sensation produced by stimulation of the organs of hearing by vibrations transmitted through the air or other medium. 2. mechanical vibrations transmitted through an elastic medium, traveling in air at a… …
85Sound — /sownd/, n. The, a strait between SW Sweden and Zealand, connecting the Kattegat and the Baltic. 87 mi. (140 km) long; 3 30 mi. (5 48 km) wide. Swedish and Danish, Oresund. * * * I Mechanical disturbance that propagates as a longitudinal wave… …
86telecommunications media — Introduction equipment and systems metal wire, terrestrial and satellite radio, and optical fibre employed in the transmission of electromagnetic signals. Transmission media and the problem of signal degradation Every… …
87Phase-locked loop — PLL redirects here. For other uses, see PLL (disambiguation). A phase locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input reference signal. It is an electronic… …
88Permittivity — A dielectric medium showing orientation of charged particles creating polarization effects. Such a medium can have a higher ratio of electric flux to charge (permittivity) than empty space In electromagnetism, absolute permittivity is the measure …
89Woofer — This article is about a loudspeaker driver. For individuals trained in remote first aid, see Wilderness First Responder. Woofer is the term commonly used for a loudspeaker driver designed to produce low frequency sounds, typically from around 40… …
90Metamaterial antenna — This Z antenna tested at the National Institute of Standards and Technology is smaller than a standard antenna with comparable properties. Its high efficiency is derived from the Z element inside the square that acts as a metamaterial, greatly… …
