236 Faraday’s Law*P31.68(a)εθθω=−°=−=NddtBAddtBaBa ddtBacoscos....1202121205201252222T mradsVV clockwiseafafThe – sign indicates that the induced emf produces clockwise current, to make its ownmagnetic field into the page.(b)At this instant θω===t202505rad ssrad. The arc PQhas lengthr===025...radmmaf. The length of the circuit is 0 50 50 251 25.m mmm++=itsresistance is 125625m5mΩΩbg=. The current is 00200..V6.25 A clockwiseΩ=.*P31.69Suppose the field is vertically down. When an electron is moving awayfrom you the force on it is in the direction given byqcvB×as −×=−awaydown=leftright .Therefore, the electrons circulate clockwise.FIG. P31.69(a)As the downward field increases, an emf is induced to produce some current that in turnproduces an upward field. This current is directed counterclockwise, carried bynegative electrons moving clockwise. Therefore the original electron motion speeds up.(b)At the circumference, we have Fmacc∑=:qvBmvrcsin902°=
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .