[Physics Class Notes] on Electrostatic Conductor Pdf for Exam

An object or a type of material that allows the flow of charge in one or more directions is known as a conductor. Common electrical conductors are materials made up of metal. Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and in some cases positive or negative ions.

It is not necessary for one charged particle to travel from the machine producing the current to that consuming it for the current to flow. To power the machine, the charged particle simply needs to nudge its neighbor a finite amount who will nudge its neighbor until a particle is nudged into the consumer.

Coulomb’s Law of Electrostatics

We begin with the magnitude of the electrostatic force between two point charges q and Q. We can conveniently label one of these charges, Q a source charge and label q, as a test charge. If r is the distance between two charges, then the force of electrostatic formula is:

[F = frac{1}{4 pi epsilon_{0}} frac{qQ}{r^{2}} = k frac{qQ}{r^{2}}]

[F = kfrac{q_{1}q_{2}}{d^{2}}].

Electrostatic Properties of a Conductor

In the static condition, a conductor neutral or charged, the electric field inside the conductor is zero everywhere, this is also one of the primary properties of a conductor. In the presence of an electric field, we know that the free electrons which a conductor contains, experiences a drift or a force. The electrons distribute themselves in such a way Inside the conductor that the final electric field is zero at all points inside the conductor.

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If the electric field lines were not normal at the surface, then we can say that a component of the electric field would have been present along the surface of a conductor in static conditions.. Since there are no tangential components, the forces have to be normal to the surface.

At every point, any neutral conductor contains an equal amount of positive and negative charges, even in an infinitesimally small element of surface area or volume. From Gauss’s law we can say that in case of a charged conductor, the excess charges are present only on the surface. Consider, any arbitrary volume element of the conductor, denoted as ‘v’, and the electrostatic field is zero for the closed surface bounding the volume element. The total electric flux through S is therefore zero. From the Gauss law, it signifies that the net charge enclosed by the surface element is zero.  At a point, we can say that the element is vanishingly small,  it denotes any point in the conductor as we go on decreasing the size of the volume and the surface element. So the net charge inside the conductor is always zero at any point and the excess charges reside at the surface.

Throughout the volume of the conductor, the electrostatic potential at any point is always constant and at any point inside the volume, the value of the electrostatic potential at the surface is equal to that.

Fun Facts

• Free charges are allowed to move about within a conductor.

• Until static equilibrium is reached, free charges are caused to move around inside the conductor by the electrical forces around a conductor. 

• All excess charges are collected along the surface of a conductor.

• More charges can be collected at the points of the conductors which has a sharp corner or point.

• A lightning rod is a conductor with sharply pointed ends that allows the excess charge to dissipate back into the air collected on the building caused by an electrical storm.

• Due to changes in the insulating effect of the air, the electrical field of Earth’s surface in certain locations becomes more strongly charged and results in electrical storms.

• A Faraday cage acts as a shield around an object, preventing the electric charge from penetrating inside. Faraday cage is a metal shield which prevents electric charge from penetrating its surface.