. The Ontario high school physics. Fig. 487.—Oersteds 404 THE ELECTRIC CDRRENT currents, but also to compare roughly their strengths, bynoting the relative deflections produced. 476. Local Action. We have noted that a plate of com-mercial zinc dissolves when immersed in dilute acid, becauseelectric currents are set up between the zinc and the impuritiesin electrical contact with it. Such currents are known aslocal currents, and the action is known as local action. Thislocal action is wasteful. It may, to a great extent, be pre-vented by amalgamating the zinc. This is done by washi
. The Ontario high school physics. Fig. 487.—Oersteds 404 THE ELECTRIC CDRRENT currents, but also to compare roughly their strengths, bynoting the relative deflections produced. 476. Local Action. We have noted that a plate of com-mercial zinc dissolves when immersed in dilute acid, becauseelectric currents are set up between the zinc and the impuritiesin electrical contact with it. Such currents are known aslocal currents, and the action is known as local action. Thislocal action is wasteful. It may, to a great extent, be pre-vented by amalgamating the zinc. This is done by washingthe plate in dilute sulphuric acid, and then rubbing mercuryover its surface. The mercury dissolves the zinc, and forms aclean uniform layer of zinc amalgam about the plate. Thezinc now dissolves only when the circuit is closed. As thezinc of the amalgam goes into the solution, the mercury takesup more of the zinc from within and the impurities float outinto the liquid (see § 468). Thus a homogeneous surfaceremains always exposed to the acid. 477. Polarizatio
Size: 2342px × 1067px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
