Lessons in practical electricity; principles, experiments, and arithmetical problems, an elementary text-book . flection. (2.) If a stronger bar magnet, astwo similar magnets with like polestogether be used, the induced be greater than when only onemagnet is used, as will be indicatedby the galvanometer needle. Therate of motion should be the samein each case. (3.) If more than one wire bemade to cut the magnetic field, , a greater E. M. F. will be in-duced than when only one wire orturn is moved past the pole at the same speed. This will beindicated by the greater momentary
Lessons in practical electricity; principles, experiments, and arithmetical problems, an elementary text-book . flection. (2.) If a stronger bar magnet, astwo similar magnets with like polestogether be used, the induced be greater than when only onemagnet is used, as will be indicatedby the galvanometer needle. Therate of motion should be the samein each case. (3.) If more than one wire bemade to cut the magnetic field, , a greater E. M. F. will be in-duced than when only one wire orturn is moved past the pole at the same speed. This will beindicated by the greater momentary deflection of the galva-nometer needle. From the above statements, then, theinduced electromotive force is dependent upon, and it canalso be proved to be pro- cmo/m* portional to, Jl «« (a) The number of mag-netic lines of force cut, orthe strength of the field; (6) The speed or rateat which the lines of forceare cut ; ( c ) The number of wirescutting the lines of force. 280. Currents In-duced in a Coil by-Motion of a Magnet.—Instead of moving theFig. 260, the wire mayFigs. 264 and 266, and of Magnet/. Fig. 264.—The Polarity of the Induced Current Tends to Stop the Motion Producing It—Lenzs Law. wire down past the magnet mbe coiled up, as in the solenoid,connected to the now either a permanent or an electromagnet be thrustinto the solenoid, a momentary induced current will flow ELECTR DMA GNETIC IND UCTION. 297 around the galvanometer according to the conditions given in % 277. Exp. 75: Connect the students galvanometer, Fig. 153, to thesecondary coil, Fig. 266, and using the bar magnet set, Fig. 13, makeexperiments to verify all the statements given in % 277. Exp. 76 : With the same apparatus as in Exp. 75, prove statements(a) and (b) in ^[279. Using one magnet, the momentary deflectionsof the needle will be about 25 for an average thrust. Exp. 77 : To prove statement (c), % 279, substitute for the secondarycoil used in Exp. 75 the solenoid depicted in
Size: 2127px × 1175px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyo, bookyear1901
