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Larry Harson
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From Maxwell's equations you use the many derivations to get Poynting's theorem:enter image description here

Since the fields are static, the second term is zero. The third termrate at which mechanical work is also zerodone on each charge is $e\mathbf E \cdot \mathbf V= \mathbf E\cdot \mathbf J$. This needs to ensurebe zero so that the $\vec J$ remains constant$\mathbf {J}$s don't change, keeping $\mathbf B$ static. So you're left with your expression equaling zero.

From Maxwell's equations you use the many derivations to get Poynting's theorem:enter image description here

Since the fields are static, the second term is zero. The third term is also zero to ensure $\vec J$ remains constant. So you're left with your expression equaling zero.

From Maxwell's equations you use the many derivations to get Poynting's theorem:enter image description here

Since the fields are static, the second term is zero. The rate at which mechanical work is done on each charge is $e\mathbf E \cdot \mathbf V= \mathbf E\cdot \mathbf J$. This needs to be zero so that the $\mathbf {J}$s don't change, keeping $\mathbf B$ static. So you're left with your expression equaling zero.

Source Link
Larry Harson
  • 5.4k
  • 2
  • 33
  • 60

From Maxwell's equations you use the many derivations to get Poynting's theorem:enter image description here

Since the fields are static, the second term is zero. The third term is also zero to ensure $\vec J$ remains constant. So you're left with your expression equaling zero.