Dental and oral radiography - a text book for students and practitioners of dentistry (1916) (14570591748)

Identifier: dentaloral00mcco (find matches)

Title: Dental and oral radiography : a text book for students and practitioners of dentistry

Year: 1916 (1910s)

Authors: McCoy, James David

Subjects: Radiography, Dental X-rays Teeth Mouth

Publisher: St. Louis : Mosby

Contributing Library: West Virginia University Libraries

Digitizing Sponsor: LYRASIS Members and Sloan Foundation

Text Appearing Before Image:

nordinary magnets, that is, their fields have muchgreater strength, for the field of the electromag-net is equal to the sum of the field due to thecore, plus the field due to the current passingthrough the coil. Thus far we have discussed the fact that a mag-netic substance in the field of an ordinary mag-net, or a conductor carrying an electric current,is magnetized. This phenomenon, we know, isdue to magnetic induction. It is also a fact thatan electric current may be induced in a conductorby causing the latter to move through a magneticfield. It makes no difference whether this fieldcomes from an ordinary magnet or from an elec-tric charge passing through a conductor. Thisaction of a magnet or of a current on a conductor ELECTROMAGNETIC INDUCTION 39 moved in its field is called electromagnetic induc-tion. Principles of Electromagnetic Induction If the ends of a coil of wire are connected witha galvanometer (Fig. 9) and the coil is moveddown over an ordinary magnet, the galvanometer

Text Appearing After Image:

Fig. 9. A, magnet with diagrammatic illustration of magnetic lines of force sur-rounding it. B shows a coil of wire connected to a galvanometer, C. will show that a momentary electric current haspassed through the coil. The current continuesas long as the coil is in motion and ceases assoon as the coil is brought to rest. If the coil iswithdrawn from the magnet, a current is alsoinduced which flows in an opposite direction to 40 DENTAL AND ORAL RADIOGRAPHY the current which was induced when the coil wascarried down over the magnet. These induced currents are produced by thefield surrounding the magnet moving or cuttingacross the ivires composing the coil. If a cur-rent is passed through the coil it creates a mag-netic field, and on the other hand the movement

Zahn- und Mundröntgen 1916 Feldlinien um Magnete Buchillustrationen Geschichte der Technologie elektrische Energie Lehrbuch Medizin Röntgen Röntgen Röntgenstrahlen Zahnheilkunde Bilder aus dem Internetarchiv

1916

West Virginia University Libraries

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public domain