Physical Significance of Electric Field

The electric charges (positive and negative) generate an electric field in their surroundings. The physical significance of these electric charges is of two categories: under static conditions and electromagnetic non-static conditions. Coulomb’s law deals with the force between these two electric charges. An example of an electric field is in the atoms. The electric field holds the components of atoms (nucleus and electrons). This force is also responsible for the bonding of atoms. As force is a vector quantity (having magnitude and direction), an electric field is also a vector quantity. Firstly, let’s study the electric charge and electric field better to understand the physical significance of the electric field.

What is an Electric Charge?

Electric charge is the property of matter that governs how the particles of those matter behave in an electrical field. The charges can be of two types; either positive or negative. The positive charge will attract the negative and repel the positive charge and vice versa. It is a scalar quantity (magnitude present but without direction), and its SI unit is Coulomb (C) with a dimensional formula [AT].

Example: When a glass rod is rubbed with a piece of silk, the glass rod will lose its electrons, and on the other hand, the piece of silk will gain electrons. Thus, we can say that the rod will now be positively charged, whereas silk with extra electrons will be of negative charge.

Electric Field

The laws of Coulomb deal with the force that acts between two electric charges. This law is only applicable for a static (imbalanced) charge. The electric field is the production of motion of these charges, and it propagates through space at the speed of light. According to the Coulomb’s law:

• The electric charges will modify its surroundings by forming an electric field around it
• If we introduce a new charge in this region, that charge will experience some force due to the electric field produced by the previous charges

Physical Significance of the Electric Field

The physical significance of the electric field can be studied under two broad categories. These categories are as follows:

Under Static Condition

The electric field will describe the electrical environment surrounding a system of charges if they are in a stable state, which means under static conditions.

Electromagnetic Non-Static Condition

The electromagnetic waves start to travel at a speed of ‘c’ due to the accelerated motion of charges. Moreover, they can exert force on other charges under this condition. The electric and magnetic fields are associated with the transport of energy. The electric field being a charging system is independent of the test charge, and the interaction between charges is electromagnetic. As we are dealing with the time-dependent electromagnetic phenomenon, the real physical signs of the electric field need to appear. Suppose two accelerated distant charges as q1 and q2, and the effect of q1 motion will not appear instantly. The difference between this effect and the cause will be the time delay and the account of this time delay is as follows:

q1’s accelerated velocity produces these electromagnetic waves, which will travel at c up to charge q2. Moreover, it implies a force on charge q2. This is the reason for the time delay.

Both the electric and magnetic fields are not just the mathematical entities but are the tangible (real) entities. However, they can only be viewed or identified by their force effects on charges. They evolve based on their own rules and thus, possess their dynamics. They might also possess energy, so propagating electromagnetic fields carrying an energy source will be left back by the electromagnetic fields when turned on and off momentarily. Michael Faraday, an English scientist, was the first person who established the concept of field. This concept is now one of the most important parts of modern physics.

Properties of Electric Field

Some of the basic properties of an electric field are as follows:

• At any point, due to the negative source, the electric field is always directed towards the charge
• The electric field is always directed away from the charge at any point due to a positive source
• If the given charge is positive, then the direction of the force will be the same as that of the electric field
• If the given charge is negative, then the direction of the force will be opposite to that of the electric field

Conclusion

The electric field is the product of electric charges (positive and negative). These charges exert a force on their surroundings producing the electric field. There can be either an attractive or repulsive force in these electric fields. For example: When an electrically charged glass rod comes in contact with objects like bits of paper, it attracts them. The rod acquires the property of attracting after being electrically charged. The physical significance of the electric field is studied in two broad categories: under static conditions and the electromagnetic non-static condition. The property of the electric field depends upon its charges.