Introduction to Electric Charge

We know about subatomic particles such as protons,electrons and neutrons.”Protons” Have +ve charge, electrons have -ve charge and neutrons have no charge, that is they are neutral.The total charge in a material is the number of charges multiplied by the charge of one electron.

Electric charge is denoted by the letter ‘q’ or ‘Q’.

So,

Q= ne, where n is the number of electrons and e is the charge of one electron 

e= 1.6x10-19C

C is coloumb which is the standard unit of Electric charge.

Conductors and Insulators

Based on their ability to move charges through them materials can be classified as conductors and insulators.Conductors are those materials through which charge can move easily.Examples include metals, human body, tap water.Our skin is also an electrical conductor. The only non-metal that conducts electricity is graphite.

Free electrons exist in all metals, alloys, and graphite, and they can freely flow throughout the conductor. 

Insulators are those materials through which charge cannot move freely. Insulators are also called non conductors. Examples include plastic, glass, rubber.

Charged particles

Positively charged protons, negatively charged electrons, and electrically neutral neutrons make up an atom. In a core nucleus, protons and neutrons are densely packed together.A single electron’s charge is the same as a single proton’s charge, except the sign is reversed.  Electrons are drawn to the nucleus because their electrical sign is opposite that of the protons in the nucleus.When the atoms of a conductor gather together to form a solid, some of its outermost electrons are free to roam within the solid, leaving positively charged atoms behind. Conduction electrons are the name given to these mobile electrons.

Induced charges

Inducing charge is the charge on a body that influences the charge surrounding it, whereas induced charge is the charge in a conductor that is influenced by the charge on another body.

Charging of Bodies

Electrification is the transformation of a neutral body into a charged one. 

Coulomb’s Law

This equation works only for charged particles.When two charged particles come close together, they exert an electrostatic pull on each other. The signs of the charges determine the direction of the force vectors. Alternatively, if the particles have opposing charge signs, they attract each other. That is, the force vector on each particle is pointing directly at the other particle.Coulomb’s law is the equation for the electrostatic forces acting on the particles.We write the electrostatic force as

F= k(q1q2)/r2

where r denotes the particle spacing and k denotes a positive constant known as the electrostatic constant or the Coulomb constant.

Spherical Conductors

When excess charge is applied to a conducting spherical shell, the excess charge spreads uniformly across the  surface. When surplus electrons are placed on a spherical metal shell, they oppose one another and tend to migrate apart, spreading over the available surface until they are evenly distributed.The distances between all pairs of extra electrons are maximised as a result of this design. When negative charge is removed from a spherical metal shell, the positive charge is distributed uniformly across the shell’s surface.

Properties of Electric Charges

Charge is Quantized

For instance, it is possible to find a particle with no charge, a charge of 15e, or a charge of 4e, but not one with a charge of 4.57e.

Charge is Conserved

A particle’s electric charge is conservative in nature. It signifies that the charge can’t be created or eliminated in any way. The charges can be transferred from one system to another system by mechanisms like conduction, and induction.

Additive property of Charges

Directly addition is possible for charges. For example:- : a system with three charges,  q1,q2,q3. The total charge of the system can be computed using this property by adding all the three charges together.

Electric Field

It is the zone around a charged particle that experiences force from another charge particle or object. Formula of Electric Field,

E=F/q

F stands for force, while q stands for charge in the calculation above. The coulombs law is used to determine F.

Direction of E

The electric field always travels from positive to negative charge. In the case of a single positive charge, the electric field moves away from the positive charge, and towards the negative charge.

Conclusion

From the article we get an idea about electric charges, their properties, about electric fields, Coulomb’s law and conductors and insulators.The strength of an object’s electrical interaction with a particle is determined by its electric charge, which can be positive or negative.