- #1
x_engineer
- 55
- 8
Just a thought experiment...
Cover a metal plate with a material of relative permittivity 0 on one side. Then place a charge on the metal plate. The system as a whole will accelerate towards the metal side since there is no flux on the covered side and so the charge is accelerated in the direction of the uncovered side. This is a violation of the conservation of energy principle, so it is impossible.
Extending the argument to relative permittivity simply less than one instead of 0, there will be less flux on the covered side, so again the charge is accelerated in the direction of the uncovered side. So this must also not be possible.
But we do have materials with relative permittivity greater than one, and I could use the same argument in that case. Why can I not, or why is it invalid to extend the argument for 0 permittivity to finite permittivity?
Cover a metal plate with a material of relative permittivity 0 on one side. Then place a charge on the metal plate. The system as a whole will accelerate towards the metal side since there is no flux on the covered side and so the charge is accelerated in the direction of the uncovered side. This is a violation of the conservation of energy principle, so it is impossible.
Extending the argument to relative permittivity simply less than one instead of 0, there will be less flux on the covered side, so again the charge is accelerated in the direction of the uncovered side. So this must also not be possible.
But we do have materials with relative permittivity greater than one, and I could use the same argument in that case. Why can I not, or why is it invalid to extend the argument for 0 permittivity to finite permittivity?