extremely high frequencies
41Microphone — For the indie film, see Microphone (film). Microphones redirects here. For the indie band, see The Microphones. A …
42Electromagnetic radiation and health — Electromagnetic radiation can be classified into ionizing radiation and non ionizing radiation, based on whether it is capable of ionizing atoms and breaking chemical bonds. Ultraviolet and higher frequencies, such as X rays or gamma rays are… …
43Signals intelligence in modern history — This article is a subset article of the article Signals intelligence, which addresses the unifying conceptual and technical factors and common technologies in this intelligence discipline. This article deals with signals intelligence in the… …
44Tweeter — A tweeter is a loudspeaker designed to produce high frequencies, typically from around 2,000 hertz to 20,000 hertz (20,000 Hz, generally considered to be the upper limit of the human hearing). A few tweeters can manage response up to an octave or …
45GENETIC ANCESTRY, JEWISH — Background The human genome refers to approximately three billion chemical letters (nucleotides) comprising the sequence of deoxyribonucleic acid (DNA) in almost every cell of each human being. There are four different nucleotides (adenine,… …
46Hearing range — for more detail on human hearing see Audiogram,Equal loudness contours and Hearing impairment. Hearing range usually describes the range of frequencies that can be heard by an animal or human, though it can also refer to the range of levels. In… …
47crystal — crystallike, adj. /kris tl/, n., adj., v., crystaled, crystaling or (esp. Brit.) crystalled, crystalling. n. 1. a clear, transparent mineral or glass resembling ice. 2. the transparent form of crystallized quartz. 3. Chem., Mineral. a solid body… …
48Electromagnetic radiation — Electromagnetism Electricity · …
49Tesla coil — at Questacon the National Science and Technology center in Canberra, Australia Uses Application in educational demonstrations, novelty lighting, as well as music Inventor …
50Gramophone record — A 12 inch (30 cm) 33⅓ rpm record (left), a 7 inch 45 rpm record (right), and a CD (above) A gramophone record, commonly known as a phonograph record (in American English), vinyl record (in reference to vinyl, the material most commonly used after …
