本帖最後由 小莓。改 於 21-4-2009 18:54 編輯
20條標準ANS : 經某校老師及同學驗證:
As there is a word "within" there, so only resistance can work on that question.
Therefore current flown = 2.5A
我錯了...是B
我老師講了一個PT : variating current
19條 switch is open = measures the emf of the cell = 12V
算把啦, 根本就唔知出卷人點諗, 係咁討論就冇用, 再唔係可能有d題cancel呢