Assume the resistance of the conducting wire and battery are both zero and an ideal voltmeter is used( i.e. Resistance of voltmeter= )
I1 = 3V I2 = 0V ( Voltmeter drawn all current)
Potential Difference=3V
∴ A voltage of 3V can be measured.
is this correct??
or I1 = I2 because current is constant in series circuit voltmeter draw all p.d. instead ( as R=infinity)
BVEsun
2009-11-20 11:27
I1 should be 0A <--- current should be in ampere unit
I2 = 0A also
since it is ideal voltmeter, so resistance of voltmeter = infinity
also the statement you mention, I1=I2 in series circuit
Grape
2009-11-20 11:58
引用第1樓BVEsun於2009-11-20 11:27發表的“”: I1 should be 0A <--- current should be in ampere unit I2 = 0A also since it is ideal voltmeter, so resistance of voltmeter = infinity .......
Volt not current-.-
Chelsea
2009-11-20 14:03
I1,2 都係 0A
Grape
2009-11-20 17:37
i am using I1 I2 to indicate the two points
i want to find voltage not current
BVEsun
2009-11-20 21:02
引用第4樓Grape於2009-11-20 17:37發表的“”: [表情] [表情] [表情] i am using I1 I2 to indicate the two points [表情] i want to find voltage not current [表情]
all notation in Physics have special meaning
I is stand for current
please don't use your own notation or no others can understand the meaning
rBB
2009-11-20 21:08
the p.d. can be anything you like
智者
2009-11-20 21:23
既然你話係ideal voltmeter
V=IR
As R=infinity
V=infinity or 0 (呢個有d tricky)
As V can't be infinity (impossible to have infinite energy --- V=Joule/C)
引用第9樓智者於2009-11-20 21:57發表的“”: but "undefined" contradicts the real world (voltmeter 會跳下跳下?咁我地就唔會有能源危機了) [表情] .......
Practically, the conducting wire and the battery bith have resistance. ∴It will draw current from the battery and there will be energy loss. It is mostly turned into heat energy by heating up the conducting wire.???
???
Grape
2009-11-20 23:05
V=IR
R tends to infinity
I tends to 0
-------------------------------
V before entering voltmeter =3
V after leaving voltmeter tends to 0(R tends to infinity)