Conductor:

Conductor: Conductors and those materials which allow electricity (charge) to pass through themselves.

Examples: (a) Metals like silver, iron, copper (b) Earth (especially the moist part) acts like a huge conductor.

Silver is the best conductor.

Insulator or Dielectric: Insulators are those materials which do not allow electricity to flow through themselves.

Examples: wood, paper, mica, glass, ebonite.

Coulomb’s law: According to Coulomb’s law, the force of attraction or repulsion between two point charges at rest is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. This force acts on the line joining the two charges.

Electric Field: Region in space around a charge of charged body where the charge has its electrical effect is called electric field of the charge.

Electric Field Intensity: Electric field intensity at a point an electric field is the force experienced by a unit positive charge placed at that point.

Electric field of hollow conductor

 Electric filed intercity inside a charged hollow conductor is zero. Charge given to such a conductor (or conductor of any shape) remains on its surface only.

This explains why a hollow conductor acts as an electrostatic shield. It is for this reason that it is safer to sit in a car or bus during lightning.

Electric Potential: Electric potential at a point in an electric field is the work done in bringing a unit positive charge from infinity to that point.

SI unit of electric potential is volt. It is a scalar quantity.