high-frequency heating
41Electromagnetic spectrum — The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation frequencies. [cite web|url=http://imagine.gsfc.nasa.gov/docs/dict ei.html#em spectrum|title=Imagine the Universe! Dictionary] The electromagnetic spectrum… …
42Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
43Cavity magnetron — Magnetron with section removed (magnet is not shown) …
44geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… …
45Microwave — This article is about the electromagnetic wave. For the cooking appliance, see Microwave oven. For other uses, see Microwaves (disambiguation). A microwave telecommunications tower on Wrights Hill in Wellington, New Zealand Microwaves, a subset… …
46Neon sign — …
47Plasma (physics) — For other uses, see Plasma. Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. The colors are a result of relaxation of electrons in excited states to lower energy states after they have recombined… …
48wood — wood1 woodless, adj. /wood/, n. 1. the hard, fibrous substance composing most of the stem and branches of a tree or shrub, and lying beneath the bark; the xylem. 2. the trunks or main stems of trees as suitable for architectural and other… …
49Wood — /wood/, n. 1. Grant, 1892 1942, U.S. painter. 2. Leonard, 1860 1927, U.S. military doctor and political administrator. * * * I Hard, fibrous material formed by the accumulation of secondary xylem produced by the vascular cambium. It is the… …
50Compact fluorescent lamp — Low energy light bulb redirects here. For other low energy bulbs, see LED lamp. The tubular type compact fluorescent lamp is one of the most popular types in Europe …
