- Inside a conductor, electrostatic field is zero
- At the surface of a charged conductor, electrostatic field must be normal to the surface at every point
- The interior of a conductor can have no excess charge in the static situation
- Electrostatic potential is constant throughout the volume of the conductor and has the same value (as inside) on its surface
- Electric field at the surface of a charged conductor
- Electrostatic shielding
A 4 µF capacitor is charged by a 200 V supply. It is then disconnected from the supply, and is connected to another uncharged 2 µF capacitor. How much electrostatic energy of the first capacitor is lost in the form of heat and electromagnetic radiation?
A spherical conducting shell of inner radius r1 and outer radius r2 has a charge Q.
(a) A charge q is placed at the centre of the shell. What is the surface charge density on the inner and outer surfaces of the shell?
(b) Is the electric field inside a cavity (with no charge) zero, even if the shell is not spherical, but has any irregular shape? Explain.
A 12 pF capacitor is connected to a 50 V battery. How much electrostatic energy is stored in the capacitor? If another capacitor of 6 pF is connected in series with it with the same battery connected across the combination, find the charge stored and potential difference across each capacitor.
a) Show that the normal component of electrostatic field has a discontinuity from one side of a charged surface to another given by
Where `hatn` is a unit vector normal to the surface at a point and σ is the surface charge density at that point. (The direction of `hatn` is from side 1 to side 2.) Hence show that just outside a conductor, the electric field is σ `hatn/in_0`
(b) Show that the tangential component of electrostatic field is continuous from one side of a charged surface to another.