Electric Field Due to a Point Charge
The electric field produced by a point charge q can be obtained in general terms from Coulomb’s law.
First note that the magnitude of the force exerted by the charge q on a test charge q_{0} is
then divide this value by q_{0} to obtain the magnitude of the field.
If q is positive, E is directed away from q. On the other hand, if q is negative, then E is directed towards q.

COULOMB’S LAW
COULOMB’S LAW: Two point electric charges q1 and q2 at rest, separated by a distance r exert a force on each other whose magnitude is given by If between the two charges there is free space then Where ε0 is the absolute electric permittivity of the free space and ε0 = 8.85 x 1012 C2 … Continue reading COULOMB’S LAW

If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why?
If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why? Answer: This is an example of frictional electricity and induction. When we comb our hair, it gets positively charged by rubbing. When the comb is brought near the pieces of paper … Continue reading If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why?

Can two similarly charged bodies attract each other?
Yes, when the charge on one body Q is much greater than that on the other q and they are close enough to each other so that force of attraction between Q and induced charge on the other exceeds the force of repulsion between Q and q. However, two similar point charges can never attract … Continue reading Can two similarly charged bodies attract each other?

Charging of Insulators
Charging of Insulators Since charge cannot flow through insulators, neither conduction nor induction can be used to charge, insulators, so in order to charge an insulator friction is used. Whenever an insulator is rubbed against a body exchange of electrons takes place between the two. This results in appearance of equal and opposite charges on … Continue reading Charging of Insulators

Charging by Contact
Charging by Contact When a negatively charged ebonite rod is rubbed on a metal object, such as a sphere, some of the excess electrons from the rod are transferred to the sphere. Once the electrons are on the metal sphere, where they can move readily, they repel one another and spread out over the sphere’s … Continue reading Charging by Contact

Charging by Rubbing
Charging by Rubbing The simplest way to charge certain bodies is to rub them against each other. When a glass rod is rubbed with a silk cloth, the glass rod acquires some positive charge and the silk cloth acquires negative charge by the same amount. The explanation of appearance of electric charge on rubbing is … Continue reading Charging by Rubbing

Conductors and Insulators
Conductors and Insulators Solids are mainly classified into two groups, conductors and insulators. In conductors, electric charges are free to move from one place to another, whereas in insulators they are tightly bound to their respective atoms. In an uncharged body, there are equal number of positive and negative charges. The examples of conductors of … Continue reading Conductors and Insulators

Electric Field Due to a Point Charge
Electric Field Due to a Point Charge The electric field produced by a point charge q can be obtained in general terms from Coulomb’s law.First note that the magnitude of the force exerted by the charge q on a test charge q0 is then divide this value by q0 to obtain the magnitude of the … Continue reading Electric Field Due to a Point Charge

Electric Field Due to a Charged Ring
Electric Field Due to a Charged Ring A conducting ring of radius R has a total charge q uniformly distributed over its circumference. We are interested in finding the electric field at point P that lies on the axis of the ring at a distance x from its centre. We divide the ring into infinitesimal … Continue reading Electric Field Due to a Charged Ring

Electric Field of a Line Charge
Electric Field of a Line Charge Positive charge q is distributed uniformly along a line with length 2a, lying along the yaxis between y=–a and y=+a. We are here interested in finding the electric field at point P on the xaxis. Derivation of electric field due to a line charge: Thus, electric field is along … Continue reading Electric Field of a Line Charge