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Ethnologue (2023) The following languages are listed as having 45 million or more total speakers in the 26th edition of Ethnologue published in 2023. This section does not include entries that Ethnologue identifies as macrolanguages encompassing all their respective varieties, such as Arabic, Lahnda, Persian, Malay, Pashto, and Chinese.
Highest military expenditure, share of GDP. The following lists are lists of countries by military spending as a share of GDP - more specifically, a list of the 15 countries with the highest share in recent years - the amount a country has spent on its military as a share of its GDP. The first list uses SIPRI as a source.
Satellite image of Berlin, with the Wall's location marked in yellow West and East Berlin borders overlaying a current road map The Berlin Wall (German: Berliner Mauer, pronounced [bɛʁˌliːnɐ ˈmaʊɐ] ) was a guarded concrete barrier that encircled West Berlin of the Federal Republic of Germany (FRG; West Germany) from 1961 to 1989, separating it from East Berlin and the German Democratic ...
- Discovery and Development
- Physics
- Common Uses
- Medical Issues and Safety
- Magnetizing Ferromagnets
- Demagnetizing Ferromagnets
- Types of Permanent Magnets
- Electromagnets
- Units and Calculations
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Ancient people learned about magnetism from lodestones (or magnetite) which are naturally magnetized pieces of iron ore. The word magnet was adopted in Middle English from Latin magnetum "lodestone", ultimately from Greek μαγνῆτις [λίθος] (magnētis [lithos]) meaning "[stone] from Magnesia", a place in Anatolia where lodestones were found (today Man...
Magnetic field
The magnetic flux density (also called magnetic B field or just magnetic field, usually denoted B) is a vector field. The magnetic B field vectorat a given point in space is specified by two properties: 1. Its direction, which is along the orientation of a compass needle. 2. Its magnitude (also called strength), which is proportional to how strongly the compass needle orients along that direction. In SI units, the strength of the magnetic B field is given in teslas.
Magnetic moment
A magnet's magnetic moment (also called magnetic dipole moment and usually denoted μ) is a vector that characterizes the magnet's overall magnetic properties. For a bar magnet, the direction of the magnetic moment points from the magnet's south pole to its north pole, and the magnitude relates to how strong and how far apart these poles are. In SI units, the magnetic moment is specified in terms of A·m2(amperes times meters squared). A magnet both produces its own magnetic field and responds...
Magnetization
The magnetization of a magnetized material is the local value of its magnetic moment per unit volume, usually denoted M, with units A/m. It is a vector field, rather than just a vector (like the magnetic moment), because different areas in a magnet can be magnetized with different directions and strengths (for example, because of domains, see below). A good bar magnet may have a magnetic moment of magnitude 0.1 A·m2 and a volume of 1 cm3, or 1×10−6 m3, and therefore an average magnetization m...
Magnetic recording media: VHS tapes contain a reel of magnetic tape. The information that makes up the video and sound is encoded on the magnetic coating on the tape. Common audio cassettes also re...Credit, debit, and automatic teller machinecards: All of these cards have a magnetic strip on one side. This strip encodes the information to contact an individual's financial institution and conne...Older types of televisions (non flat screen) and older large computer monitors: TV and computer screens containing a cathode ray tubeemploy an electromagnet to guide electrons to the screen.Speakers and microphones: Most speakers employ a permanent magnet and a current-carrying coil to convert electric energy (the signal) into mechanical energy (movement that creates the sound). The c...Because human tissues have a very low level of susceptibility to static magnetic fields, there is little mainstream scientific evidence showing a health effect associated with exposure to static fields. Dynamic magnetic fields may be a different issue, however; correlations between electromagnetic radiation and cancer rates have been postulated due...
Ferromagneticmaterials can be magnetized in the following ways: 1. Heating the object higher than its Curie temperature, allowing it to cool in a magnetic field and hammering it as it cools. This is the most effective method and is similar to the industrial processes used to create permanent magnets. 2. Placing the item in an external magnetic fiel...
Magnetized ferromagnetic materials can be demagnetized (or degaussed) in the following ways: 1. Heating a magnet past its Curie temperature; the molecular motion destroys the alignment of the magnetic domains. This always removes all magnetization. 2. Placing the magnet in an alternating magnetic field with intensity above the material's coercivity...
Magnetic metallic elements
Many materials have unpaired electron spins, and the majority of these materials are paramagnetic. When the spins interact with each other in such a way that the spins align spontaneously, the materials are called ferromagnetic (what is often loosely termed as magnetic). Because of the way their regular crystalline atomic structure causes their spins to interact, some metals are ferromagnetic when found in their natural states, as ores. These include iron ore (magnetite or lodestone), cobalt...
Composites
Ceramic, or ferrite, magnets are made of a sintered composite of powdered iron oxide and barium/strontium carbonate ceramic. Given the low cost of the materials and manufacturing methods, inexpensive magnets (or non-magnetized ferromagnetic cores, for use in electronic components such as portable AM radio antennas) of various shapes can be easily mass-produced. The resulting magnets are non-corroding but brittleand must be treated like other ceramics. Alnico magnets are made by casting or sin...
Flexible magnet
Flexible magnets are composed of a high-coercivity ferromagnetic compound (usually ferric oxide) mixed with a resinous polymer binder.This is extruded as a sheet and passed over a line of powerful cylindrical permanent magnets. These magnets are arranged in a stack with alternating magnetic poles facing up (N, S, N, S...) on a rotating shaft. This impresses the plastic sheet with the magnetic poles in an alternating line format. No electromagnetism is used to generate the magnets. The pole-to...
An electromagnet, in its simplest form, is a wire that has been coiled into one or more loops, known as a solenoid. When electric current flows through the wire, a magnetic field is generated. It is concentrated near (and especially inside) the coil, and its field lines are very similar to those of a magnet. The orientation of this effective magnet...
For most engineering applications, MKS (rationalized) or SI (Système International) units are commonly used. Two other sets of units, Gaussian and CGS-EMU, are the same for magnetic properties and are commonly used in physics.[citation needed] In all units, it is convenient to employ two types of magnetic field, B and H, as well as the magnetizatio...
How magnets are made Archived 2013-03-16 at the Wayback Machine(video)Floating Ring Magnets, Bulletin of the IAPT, Volume 4, No. 6, 145 (June 2012). (Publication of the Indian Association of Physics Teachers).The Great Wall of the Qin stretches from Lintao to Liaodong. The Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn period between the 8th and 5th centuries BC. During this time and the subsequent Warring States period, the states of Qin, Wei, Zhao, Qi, Han, Yan, and Zhongshan all constructed extensive fortifications to defend their own borders.
Canva is a graphic design platform that provides tools for creating social media graphics, presentations, promotional merchandise and websites. [6] [7] [8] Launched in Australia in 2013, the service offers design tools that are easy-to-use for individuals and companies. [9] Its offerings include templates for presentations, posters, and social ...
0 (zero) is a number representing an empty quantity. Adding 0 to any number leaves that number unchanged. In mathematical terminology, 0 is the additive identity of the integers, rational numbers, real numbers, and complex numbers, as well as other algebraic structures. Multiplying any number by 0 has the result 0, and consequently, division ...
