An elementary book on electricity and magnetism and their applications . smallmagnetic needle or compass is placed onthe paper with its center over a line offilings, the needle will tend to stand at atangent to the line (Fig. 45). An inde-pendent magnetic pole (if such a thingwere physically possible) would tend tomove continuously round and round thewire along any one of the lines of filingsupon which it might be placed. If the cardboard has been soaked in paraffin, the iron filings may be fixed in position for examination at leisure by passing the flame of a Bunsen gas burner quickly over th
An elementary book on electricity and magnetism and their applications . smallmagnetic needle or compass is placed onthe paper with its center over a line offilings, the needle will tend to stand at atangent to the line (Fig. 45). An inde-pendent magnetic pole (if such a thingwere physically possible) would tend tomove continuously round and round thewire along any one of the lines of filingsupon which it might be placed. If the cardboard has been soaked in paraffin, the iron filings may be fixed in position for examination at leisure by passing the flame of a Bunsen gas burner quickly over the surface, thereby softening the paraffin for an instant and allowing the filings to become embedded in it. The direction in which the magnetic needle points whennear a wire carryingan electric currentdepends upon twothings: (1) the sideof the wire on whichit stands and (2) thedirection in whichthe current flows inthe wire. In figure45 it is evident fromthe positions of themagnetic needles(the black ends rep-resent north poles)that the lines of forcerun counter to the. MERIDIAN OF K/EARTHS MAGNETISM \ ^J Fro, 45. — Magnetic lines of force which surround an electric current shown by small compassneedles, N§. ELECTROMAGNETISM 91 Direction of . Magnetic ^^>
Size: 1428px × 1749px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectmagnetism, bookyear19
