A text-book of physics, largely experimentalOn the Harvard college "Descriptive list of elementary physical experiments." . 0 Fig. 264. a way that the current through the galvanoscope can be easilyreversed (see Fig. 264). Read very carefully and record the position of the needle, tappingthe instrument lightly, as usual; then, by means of the commutator,reverse the current through the galvanoscope, and again read andrecord. Make similar arrangements and readings with each of the otherpieces of German-silver wire in turn, proceeding from the longest tothe shortest. RESISTANCE. 491. Tf time permi
A text-book of physics, largely experimentalOn the Harvard college "Descriptive list of elementary physical experiments." . 0 Fig. 264. a way that the current through the galvanoscope can be easilyreversed (see Fig. 264). Read very carefully and record the position of the needle, tappingthe instrument lightly, as usual; then, by means of the commutator,reverse the current through the galvanoscope, and again read andrecord. Make similar arrangements and readings with each of the otherpieces of German-silver wire in turn, proceeding from the longest tothe shortest. RESISTANCE. 491. Tf time permits, after making observations with the shortest wire,use each of the others again in turn, ending with the longest. Take the mean of all the deflections obtained with each wire asthe true deflection with that wire. On a piece of coordinate paper, ruled in very small squares, meas-ure off horizontal distances, as in Fig. 265, to represent the variouslengths of wire, and above the points marked 40, 80, etc., place dotsat vertical distances repre-senting the deflections corre-sponding to the various through these pointsdraw a curve of such a char-acter, A or B, as the factsrequire. By measurement from anypoint on the base-line up tothis curve one can now findwhat deflection would corre-spond to a wire of any givenlength between 40 cm. and 200 cm. This diagram will be of use inconnection with the next Exercise. Note.—Each porous cup used in this Exercise should be marked,so that the student who uses it may find and use the same cup in thenext Exercise. The Daniel
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectphysics
