image Quasi-electrostatics

  • In quasi-electrostatics, we consider charge flow but ignore magnetic effects, treating it similarly to electrostatics. Skipping section 7.2.

The ideal conductor condition appears as a state when t approaches infinity.

The field outside the conductor’s surface (i.e., the influence of surface charge) is smaller compared to the field inside, and since the physics is complex, we temporarily ignore it.

  • In this case, does the geometry no longer matter?

For a non-planar conductor:

  • If we bring conditions like curl = 0, the current density must be the same for every part of the conductor.
    • Where does curl = 0 come from again?
    • Is it for an ideal conductor?
  • Otherwise, charge will accumulate.

If the left and right sides of the conductor are open (connected to other things), the ideal conductor conduction is no longer relevant.

While the potential decreases, the magnitudes of E (electric field) and p (polarization) remain constant, but the energy decreases.

  • Well, that makes sense.
  • That is the potential energy.

EMF ε + Δφ = 0

  • If we transform it, we get familiar equations like P = εI.

Micro Ohm’s law: E = σJ

  • Integral of E dx = V
  • image Macro Ohm’s law: V = iR

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  • It’s a bit different from the calculations in the textbook.