We explain what an electric field is, the history of its discovery, how its intensity is measured and what its formula is.
What is an electric field?
An electric field is a physical field or region of space that interacts with electric charges or charged bodies through an electric force. Its representation through a model describes the way in which different bodies and systems of an electrical nature interact with it.
Said in physical terms, is a vector field in which a given electric charge (q) suffers the effects of an electric force (F).
These electric fields can be a consequence of the presence of electric charges, or of variable magnetic fields, as demonstrated by the experiments of British scientists Michel Faraday and James C. Maxwell.
For that reason, electric fields, in contemporary physical perspectives, are considered together with magnetic fields to form electromagnetic fields.
Thus, an electric field is that region of space that has been modified by the presence of an electric charge. If this charge is positive, it generates electric field lines that “aren” in the charge and extend outward in a radial direction. If, on the other hand, the charge is negative, the field lines “die” in the charge. If a charge approaches the region of space where an electric field exists, it will experience an electric force with a direction and sense.
See also: Electromagnetism
History of the electric field
The concept of electric field It was first proposed by Michel Faraday arising from the need to explain the action of electrical forces at a distance. This phenomenon was key in his demonstration of electromagnetic induction in 1831, with which proven the links between magnetism and electricity.
A later contribution to the electric field was that of James Maxwell, whose equations described multiple aspects of the electrical dynamics of these fields, especially in their Dynamic theory of the Electromagnetic Field (1865).
Electric field units
electric fields are not directly measurable with any type of device. But yes it is possible to observe its effect on a load located in its vicinity, that is, it is possible to measure the force acting on the load (intensity). For this, newton/coulomb (N/C) is used.
Electric field formula
The equation that relates an electric field E with the force it exerts on a charge q is given by the following equation:
F = qE
Where F is the electric force that acts on the electric charge q introduced into the field with a intensity E. Let us note that both F and E are vector magnitudes, endowed with meaning and direction.
From there, it is possible to advance mathematically by incorporating Coulomb's Law, obtaining that E = F/q = 1/4πϵ0 = (qYo/r2).ȓYowhere ȓYo are the unit vectors that mark the direction of the line that joins each charge qYo with each charge q.
Electric field intensity
The intensity of the electric field is a vector magnitude that represents the electric force F acting on a given charge in a precise Newton/Coulomb (N/C) quantity. This magnitude is usually simply called “electric field”, because the field itself cannot be measured, but rather its effect on a given charge.
To calculate it, the formula F = qE is used taking into account that if the charge is positive (q > 0), the electric force will have the same sign as the field and q will move in the same direction; while if the charge is negative (q < 0), everything will happen the other way around.
Electric field example
A simple example of calculation of the intensity of an electric field is:
If we introduce an electric charge of 5×10-6 C In an electric field that acts with a force of 0.04 N, with what intensity does said field act?
Applying the formula E = F/q, we have that E = 0.04 N / 5×10-6 C = 8,000 N/C.
Continue with: Electric current
References
- “Electric field” in Wikipedia.
- “Electric field” (video) in Educatina.
- “What is an electric field” in BioProfe.
- “The electric field” at Khan Academy.
- “Electric Field” in Hyperphysics.
- “Electric Field” in The Encyclopaedia Britannica.
