. Dental and oral radiography : a textbook for students and practitioners of dentistry . g. 7) it follows that asolenoid is capable of magnetizing pieces of soft ironand attracting them in the same way as does an ordinarysteel magnet. The magnetic field of a solenoid isstrongest within its windings and therefore if a bar ofsoft iron is placed within the coil, the bar will be muchmore strongly magnetized than if placed in any otherposition about the coil. Such a coil adapted to carry acurrent and provided with a soft iron bar or core iscalled an electromagnet (Fig. 8). 38 DENTAL AND OKAL RADIOG
. Dental and oral radiography : a textbook for students and practitioners of dentistry . g. 7) it follows that asolenoid is capable of magnetizing pieces of soft ironand attracting them in the same way as does an ordinarysteel magnet. The magnetic field of a solenoid isstrongest within its windings and therefore if a bar ofsoft iron is placed within the coil, the bar will be muchmore strongly magnetized than if placed in any otherposition about the coil. Such a coil adapted to carry acurrent and provided with a soft iron bar or core iscalled an electromagnet (Fig. 8). 38 DENTAL AND OKAL RADIOGRAPHY Iii order to permii the wire to be closely wound andat the same time to allow the current to pass througheach turn, the wire must be covered with insulationthroughout its length. It should also be rememberedthat the iron core within the solenoid remains a magnetonly while the current is passing through the coil, asonly electric charges in motion product magneticeffects. Electromagnets are much more powerful than ordinarymagnets: that is, their fields have much greater strength,. Fig. — An iron bar placed within the windings of a solenoid is subject to its mag-netic field and becomes a magnet. for the field of the electromagnet is equal to the sum ofthe field due to the core, plus the field due to the currentpassing through the coil. Thus far we have discussed the fact that a magneticsubstance in the held of an ordinary magnet, or a con-ductor carrying an electric current, is magnetized. Thisphenomenon, we know, is due to magnetic induction. Itis also a fact that an electric current may be induced ina conductor by causing the latter to move through a mag-netic field. It makes no difference whether this fieldcomes from an ordinary magnet or from an electriccharge passing through a conductor. This action of a HIGH TENSION ELECTRIC CURRENTS 39 magnet or of a current on a conductor moved in its fieldis called electromagnetic induction. Principles of Electromagnetic Induct
Size: 2061px × 1212px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthormcc, bookcentury1900, bookdecade1910, bookiddentalorcco
