vector analysis---WRONG!!!

Status
Not open for further replies.

kolahalb

Junior Member level 1
Joined
Feb 25, 2007
Messages
17
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,407
What is the wrong in the proof that there is no magnetic field?
We know:
div B=0 and B=curl A where B is the magnetic field and A is its vector potential
Then,∫div B dV=0=∫B.n dA(divergence theorem)
Thus, 0=∫(curl A).n dA
=∫A.dr(Stokes' theorem)
The last will be a cyclic integral.
Since the cyclic line integral is zero,A is conservative;
or,A=grad f
Then,B=curl A=curl grad f=0
or,B=0

I think the problem lies between the equality in Stokes' theorem.In original Stokes' theorem LHS is a non-cyclic integral whereas here it comes directly from divergence theorem and is a cyclic integral...
Please let me know if i am correct;if not,then where did I go wrong.
Thank you in advance
 

You are right that you have to be careful about closed and non closed line/path integral. Further more it will be an error to assume that
∫div B dV=0, rather this integral should be constant. Any way, since there are more than one flaws in the proof the argument is not proved and hence false.
 

I did not understand why ∫div B dV is not zero.For a closed volume there is no magnetic monopole that will make the divergence non-zero.
 

kolahalb said:
I did not understand why ∫div B dV is not zero.For a closed volume there is no magnetic monopole that will make the divergence non-zero.

Yes, I was trying to say it is zero or constant in general and in this case it is zero when you work with

∫© B.da which will be zero.
 

Status
Not open for further replies.

Similar threads

Cookies are required to use this site. You must accept them to continue using the site. Learn more…