03) magnetics(resnick halliday walker) kho tài liệu bách khoa
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: 03) magnetics(resnick halliday walker) kho tài liệu bách khoa
03) magnetics(resnick halliday walker) kho tài liệu bách khoa
ị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoaorthern or southern latitudes, but they are quite rare in the middle latitudes What causes these shimmering curtains of light, and why are they usually visible onfy near the Earth's North and South poles? fCearffd tepp.'Jwrs Stans fmaass)chapter29Magnetic FieldsChapter Outline29.1The Magnetic Field2 03) magnetics(resnick halliday walker) kho tài liệu bách khoa9.2Magnetic Force Acting on a Current-Carrying Conductor29.3Torque on a Current Loop in a Uniform Magnetic Field29.4Motion of a Charged Particle in a03) magnetics(resnick halliday walker) kho tài liệu bách khoa
Uniform Magnetic Field29.5(Optional) Applications Involving Charged Particles Moving in a Magnetic Field29.6(Optional) The Hall Effect904Magnetic Fielị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoa being of Arabic or Indian origin. The early Greeks knew about magnetism as early as 800 B.c. They discovered that the stone magnetite (FC3O4) attracts pieces of iron. Legend ascribes the name magnetite to the shepherd Magnes, the nails of whose shoes and the tip of whose stair stuck fast to chunks 03) magnetics(resnick halliday walker) kho tài liệu bách khoaof magnetite while he pastured his flocks.in 1269 a Frenchman named Pierre de Maricourt mapped out the directions taken by a needle placed at various03) magnetics(resnick halliday walker) kho tài liệu bách khoa
points on the surface of a spherical natural magnet. He found that the directions formed lines that encircled (he sphere and passed through two pointsị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoahas two poles, called north and south poles, (hat exert forces on other magnetic poles just as electric charges exert forces on one another. That is. like poles repel each other, and unlike poles attract each other.The poles received their names because of the way a magnet behaves in the presence of 03) magnetics(resnick halliday walker) kho tài liệu bách khoa the Earth’s magnetic field. If a bar magnet is suspended from its midpoint and can swing freely in a horizontal plane, it will rotate until its north03) magnetics(resnick halliday walker) kho tài liệu bách khoa
pole points to the Earth's geographic North Pole and its south pole points to the Earth’s geographic South Pole.1 (The same idea is used in the constị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoacompass needle orients in preferred directions, he suggested (hat the Earth itself is a large permanent magnet. In 1750 experimenters used a torsion balance to show that magnetic poles exert attractive or repulsive forces on each other and that these forces vary as the inverse stpiare of the distanc 03) magnetics(resnick halliday walker) kho tài liệu bách khoae between interacting poles. Although the force between two magnetic poles is similar to the force between two electric charges, (here is an important03) magnetics(resnick halliday walker) kho tài liệu bách khoa
difference. Electric charges can be isolated (witness the electron and proton), whereas a single magnetic pole has never been isolated. That is. magnị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoarmanent magnet is cut in two. each piece always has a north and a south pole. (There is some theoretical basis for speculating that magnetic monopoles—isolated north or south poles—may exist in nature, and attempts to detect (hem currently make up an active experimental field of investigation.)The r 03) magnetics(resnick halliday walker) kho tài liệu bách khoaelationship between magnetism and electricity was discovered in 1819 when, during a lecture demonstration, the Danish scientist Hans Christian Oersted03) magnetics(resnick halliday walker) kho tài liệu bách khoa
found that an electric current in a wire deflected a nearby compass needle.2 Shortly thereafter. Andre Ampere (1775-1836) formulated quantitative lawị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoatric current loops are responsible for all magnetic phenomena.In the 1820s. further connections between electricity and magnetism were demonstrated by Faraday and independently by Joseph Henry (1797-1878). They1 Note that the Earth's geographic North Pole is magnetically a south pole. whereas its ge 03) magnetics(resnick halliday walker) kho tài liệu bách khoaographic South Pole is magnetically a north pole. Because ffpfwute magnetic poles attract each other, the pole on a magnet that is attracted to the Ea03) magnetics(resnick halliday walker) kho tài liệu bách khoa
rth's geographic North Pole is the magnet's nortA pole and the pole attracted to the Faith's geographic South Pole is the magnet's unith pole.•The samị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoa dr 'nmtmo rather than 111 a scholarly journal905An electromagnet is used to move ton* of scrap metal.Hans Christian OerstedDanish physicist (1777-18511 /Horfi VM Acrure AretMeif906CHAPĨÍR Ĩ9 Magnetic FieldsỌuickLabIf iron or Steel is left in .1 weak magnetic field (such as that due to the Farth) lo 03) magnetics(resnick halliday walker) kho tài liệu bách khoang enough, it fan become magnetized. Use a compass tv see il sou can detect a magnetic field neat a steel lile cabinet, cast itvn radiator. Of some od03) magnetics(resnick halliday walker) kho tài liệu bách khoa
iei piece OÍ Ictrous metal that lias been in one position lot several tears.shotted thill ail electric current can be produced in a circuit either by ị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoas an electric field. Years later, theoretical work by Maxwell showed that the reverse is also Hue: A changing electric field creates a magnetic Field.A similarity between electric and magnetic Hirers has provided methods of making permanent magnets. In Chapter 23 we learned that when rubber and wool 03) magnetics(resnick halliday walker) kho tài liệu bách khoa are rubbed together, both become charged—one positively and the other negatively. In an analogous fashion, one can magnetize an unmagnerized piece of03) magnetics(resnick halliday walker) kho tài liệu bách khoa
iron by stroking it with a magnet. Magnetism can also be induced in iron (and other materials) by other means. For example, if a piece of umnagnelizeị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoact on moving charges and on current-carrying wires in the presence of a magnetic field. The source of the magnetic field itself is described in Chapter 30.29.1^ THE MAGNETIC FIELDJ' In our study of electricity, we described the interactions between charged objects 122 in terms of electric fields. Re 03) magnetics(resnick halliday walker) kho tài liệu bách khoacall that an electric field surrounds any stationary or moving electric charge. In addition to an electric field, the region of space surrounding any03) magnetics(resnick halliday walker) kho tài liệu bách khoa
moving electric charge also contains a magnetic field, as we shall see in Chapter 30. A magnetic field also surrounds any magnetic substance.Historicaị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far no 03) magnetics(resnick halliday walker) kho tài liệu bách khoaany location is the direction in which a compass needle points at that location. Figure 29.1 shows how the magnetic field of a bar magnet can be traced with the aid of a compass. Note that the magnetic field lines outside the magnet point away from north poles and toward south poles. One can display 03) magnetics(resnick halliday walker) kho tài liệu bách khoa magnetic field patterns of a bar magnet using small iron filings, as shown in Figure 29.2.ị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far noị p u z z L E RAurora Borealis, the Northern Lights, photographed near Fairbanks. Alaska. Such beautiful auroral displays are a common sight «1 far noGọi ngay
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