Lines of electric force

What is a charge? Electric charge is a physical characteristic of matter that enables it to feel a force when positioned in an electromagnetic field. The net charge of a single system cannot be changed. The symbol of charge is q. We can define the electric line of force as a path, way or direction and maybe spiralled, straight, curved. 

For instance, lighting is an example of electric discharge. This type of event indicates the enormous amount of electric charge stored in the object surrounding us. What happens when we rub a glass rod with silk? The glass rod gains a type of charge and the piece of silk cloth will gain another type of charge. Again if we bring the charge objects near each other, the charge obtained will be lost. In the 1830s, English scientist Michael Faraday introduced the concept of line of electric force. 

What is an electric charge?

When we place the matter in the electromagnetic field, the physical property of matter experiences a force known as electric charge. Electric charge is of two types, positive and negative. Protons carry a positive charge while electrons carry a negative charge where “like charges repel each other and unlike charges attract each other”. 

If any substance has no net charge, it is said to be neutral. The proton has a +e charge, while an electron has a -e charge. The value of e = 1.6×10-19 C. Electric field is produced by electric charges while magnetic fields are generated by moving charges. The S.I. unit of electric charge is the coulomb. The lowercase q is often used to denote the charge. Atoms possess the same number of protons and electrons, thus cancelling the charges and making the net charge zero. 

What is an electric line of force?

In simple words, we can say that the lines of electric force define the direction of the electric field. They are described as a line or path—the direction of a small positive charge in the direction of an electric line of force. The electric line of force appears from positive charge and ends to negative charge. 

If you need to know the direction of the resultant electric field, draw a tangent to the line of electric force. If the number of lines of electric force is more (are denser), the more will be the intensity of the electric field at that particular unit. The most important thing is that electric lines of force are just imaginary lines that represent electric fields. 

Properties of the line of electric force

• The line of electric force shrinks longitudinally and expands laterally.

• A couple of lines of electric force cannot intersect each other. 

• Two lines of electric force heading in a similar direction repel each other. 

• Two lines of electric force heading in the opposite direction attract each other. 

• The line of electric force is imaginary, but the electric field they depict is real.

Inside the conductor, the number of lines of electric force is zero.

• In the absence of a conductor, lines of electric force are continuous curves, whereas, in the presence of a conductor, they are discontinuous. 

• The number of electric field lines and the magnitude of the charge is proportional to each other. 

Electric field

An electric field is a physical field that encloses electrically charged components and applies force to other charged components. Either it attracts or repels. Electric charges are the origin-destination for electric fields. Electric fields are of great importance in atomic physics, chemistry and physics.

The electric field is characterised by force; thus, the electric field is a vector quantity (both magnitude and direction). It’s S.I. unit is represented as V/m. The electric field functions between two charges. A pack of lines whose direction at each point is identical to a field, the electric field can also be imagined like this. This concept was given by Michael Faraday. Some of the important characteristics of electric field lines are that they always start from the positive charge and end to the negative. Also, remember that electric field lines enter a conductor at 90 degrees. 

There are two types of electric fields. Uniform and non-uniform electric fields. When the electric field is steady at each point, we call it a uniform electric field. The electric field is uneven at each point; we call it a non-uniform electric field. 

Assume a unit charge Q. If any other charge, say charge q, is placed near it, then according to coulomb’s law, charge Q will apply force on it and produce an electric field around it. If any other charge is placed around it, then the electric field of Q applies force on it. The electric field generated by charge Q at a distance r is given by E=KQ/r² where k is a constant and equal to 8.9×109 Nm2/C2.

Conclusion

Hence we conclude with some points to remember about electric charge. The line of electric force is none other than the line indicating the direction of electric fields. The electric field is strong enough when the lines of force are closer and becomes weak when it moves apart and perpendicular to the surface charge. An electric field is never negative. If the charge is isolated, then it begins or ceases at infinity. In a charge-free region, line curves are continuous.