以下有5張圖:
http://i1091.photobucket.com/albums/i400/eddierr/R2.jpg?t=1291747994 fig.1
http://i1091.photobucket.com/albums/i400/eddierr/R3.jpg?t=1291747994 fig.2
http://i1091.photobucket.com/albums/i400/eddierr/R4.jpg?t=1291747994 fig.3
http://i1091.photobucket.com/albums/i400/eddierr/R5.jpg?t=1291747994 fig.4
http://i1091.photobucket.com/albums/i400/eddierr/R6.jpg?t=1291747994 fig.5
q1)先睇fig.1,如果要計equivalent resistance我地會好似fig.2咁睇因為Vc=Vd,冇current,最後應該eq r=5ohm係唔係?
q2)再睇fig3,eq r應該係2ohm而current across c 同d同Vc,Vd就好似上圖所示,then我地用一條conducting wire連住佢好似fig.4咁,問題就黎喇,
i)Vc係唔係等於Vd?
因為以我所知係wire上既any pt都應該有same potential,咁refer番q1)既解度,
ii)基於我假設Vc=Vd,係唔係冇current through pt.c&d?
iii)如果係咁,點解current會由c去y而唔會由c去d再去y?
iv)再基於我假設Vc=Vd,咁i1+i2應該=i3+i4架嘛,我計到Vc=Vd=2.67,i1=3.33,i2=0.67,i3=1.33,i4=2.67,咁i1不等於i2and i3不等於i4,咪代表有current through pt.c&d?咁究竟係有current定冇?同fig1,2計eq r果個example有咩唔同?
q3)到到last fig.5,其實係我終極唔明既問題,呢個係potentiometer,跟住length1既potential係=emf of E2,咁冇current through galvanometer啦,
i)請問點解?我唔明既係我就咁將E2同一個同length1有same resistance既resistor駁埋都有current,但點解釋呢個situation?
ii)如果Va>Vb,係唔係有current由a去b?但果度係E2既negative terminal黎架喎,咁請問current係E1整出黎既定係E2?
iii)相反,Vb>Va又會係點?
如果天同師兄可以答到我真係十分感激,因為我對"same potential,no current"呢個concept唔係好掌握到,就好似由cell到resistor果條path一路到係same potentail架啦,但係又有current,所以希望您可以幫忙!