PHY INDUCE CURRENT

By flemming's right hand rule
the induce current will move from Y to X
so 1 is incorrect
By flemming's left hand rule,
the induced current will produce a magetic force towards left
thus the resulant force is F-F by induced current
so 3 is incorrect
as the induced current moves from Y to X
electrons move from Y to X
thus X has a higher potential than Y
so 2 is correct

2010-04-07 10:07:48 補充：
yes,you are right according to the same rules
the force by induced current is still towards left by left hand rule
thus the resulant force is still F-F by induced current

Apply Fleming's Right Hand Rule to the metal rod, it can be found that the induced current flows from Y to X. Hence X is at a potential higher than Y (compare with the flow of current inside a cell). Therefore, statement (1) is wrong and statement (2) is correct.

Clearly, the resultant force on the rod is zero, as force F is balanced by the magnetic force.



2010-04-07 10:18:59 補充：
Yes, if the magnetic field is pointing out from the paper, the induced current will flow from X to Y. Then Y is at a higher potential than X.

2010-04-07 10:21:37 補充：
There are two forces acting on the rod. The first one is the applied force F pulling the rod to the right. The second is the magentic force produced by the induced current in the presence of magnetic field (you could try to use Fleming's Left hand Rule to determine its direction)....(contd)

2010-04-07 10:21:59 補充：
(cont'd)....This force opposes the applied force F.