- #1
Von Neumann
- 101
- 4
Problem:
I'm trying to crudely prove the following:
[itex]\frac{{\partial}B}{{\partial}x}[/itex]=-[itex]\mu_{o}[/itex][itex]\epsilon_{o}[/itex][itex]\frac{{\partial}E}{{\partial}t}[/itex]
Solution (so far):
I can get the derivation, but the minus sign eludes me somehow...
Integrating over a thing rectangular loop of length [itex]l[/itex] and width [itex]dx[/itex], start with the following,
[itex]\oint{B{\cdot}dl}[/itex]=[itex]\mu_{o}\epsilon_{o}[/itex][itex]\frac{\partial{\Phi_{E}}}{\partial{t}}[/itex]
Then,
[itex]\oint{B{\cdot}dl}[/itex]=[itex](B+dE)l-Bl=dEl[/itex]
Also,
[itex]\Phi_{E}=EA=E(dx)(l)[/itex]
∴[itex]\frac{\partial{\Phi_{E}}}{\partial{t}}=[/itex][itex]\frac{\partial{E}}{\partial{t}}dxl[/itex]
Equating the equations above,
[itex]dEl=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}dxl[/itex]
[itex]dE=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}dx[/itex]
[itex]\frac{\partial{E}}{\partial{x}}=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}[/itex]
Any advice is greatly appreciated.
I'm trying to crudely prove the following:
[itex]\frac{{\partial}B}{{\partial}x}[/itex]=-[itex]\mu_{o}[/itex][itex]\epsilon_{o}[/itex][itex]\frac{{\partial}E}{{\partial}t}[/itex]
Solution (so far):
I can get the derivation, but the minus sign eludes me somehow...
Integrating over a thing rectangular loop of length [itex]l[/itex] and width [itex]dx[/itex], start with the following,
[itex]\oint{B{\cdot}dl}[/itex]=[itex]\mu_{o}\epsilon_{o}[/itex][itex]\frac{\partial{\Phi_{E}}}{\partial{t}}[/itex]
Then,
[itex]\oint{B{\cdot}dl}[/itex]=[itex](B+dE)l-Bl=dEl[/itex]
Also,
[itex]\Phi_{E}=EA=E(dx)(l)[/itex]
∴[itex]\frac{\partial{\Phi_{E}}}{\partial{t}}=[/itex][itex]\frac{\partial{E}}{\partial{t}}dxl[/itex]
Equating the equations above,
[itex]dEl=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}dxl[/itex]
[itex]dE=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}dx[/itex]
[itex]\frac{\partial{E}}{\partial{x}}=[/itex][itex]\mu_{o}\epsilon_{o}\frac{\partial{E}}{\partial{t}}[/itex]
Any advice is greatly appreciated.