• The charge keeps moving until it reaches equilibrium conditions.

    • This is similar to a surface condition.
  • When there is no ground,

    • The charge is conserved.
      • The total charge of the entire system, Q, remains constant.
      • However, the electric field inside the conductor is still zero.
        • This is because the positive and negative charges on the left and right sides both contribute to it.
    • The charge inside the cavity remains the same and is transmitted to the outside.
    • The charge outside the cavity does not transmit to the inside.
  • Cavity

    • According to Gauss’s law, the total flux around the cavity, including the surface, is zero, which means the total charge is zero.
  • Image charge method

    • By assuming the existence of a non-existent symmetrical charge, we can calculate the field returning from the grounded conductor.
      • This is similar to defining a Green’s function.