引用第716樓rBB於2009-11-22 18:39發表的“”:
呢條數大家有咩高見
我覺得係a
I also agree the answer is A
VD=I * RL
VD = voltage drop by internal resistance
I = total current
RL = internal resistance
RL unchange during the switch open/closed
but, I will increase when switch closed
so voltage drop increase