Integration of a solenoidal vector field over a volume

Phillips101
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Homework Statement



div(J)=0 in volume V, and J.n=0 on surface S enclosing V, where n is the normal vector to the surface.

Show that the integral over V of J dV is zero.



Homework Equations




The Attempt at a Solution



I can't get anywhere with it! The divergence theorem doesn't seem to help, as I just go round in circles. Any help at all will really be useful.

Thanks
 
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Try applying the divergence theorem to the vector field \lambda\vec{J} What happens if you choose \lambda such that \vec{\nabla}\lambda is a constant vector?
 
Thanks for that - everything now works.
 
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