While identical charges repel each other, opposite charges end up attracting each other.
Coulomb's law is one of the pillars of the branch of physics that is defined as electrostatics , in addition to having been very valuable in developing electromagnetic theory .
Its name recalls the surname of Charles-Augustin de Coulomb , an engineer, physicist and mathematician of French origin who formulated this principle in 1785 after inventing, on his own initiative, a torsion balance . This instrument allowed him to measure both the force of attraction and the force of repulsion exerted by more than one electric charge on each other.
The content of this postulate indicates that the representative magnitude of each electric force with which a pair of specific charges interact in a state of rest is directly proportional to the product resulting from the magnitude of the charges involved. It is also inversely proportional to the square of the distance that marks a separation between them and has the same orientation (direction) as the line that connects them. If the charges are of opposite sign, then there is a force of attraction ; If there are charges with identical signs, the force is repulsive.
It should be noted that this Coulomb contribution, which is popularly known as the law of charges , is applied only when the conditions are stationary, that is, when no movement is detected in the charges.
Applications of Coulomb's law
Although it may not be easy for the average person to identify what and how Coulomb's law is, this principle is applied in a wide variety of activities, disciplines and fields.
It is very useful, to detail a specific case, in the area of electrochemistry . It is taken into account when analyzing the charging/discharging of batteries or when carrying out the process known as electrolysis , for example.
In the industry focused on the generation, distribution and marketing of electrical energy service, Coulomb's law is also important and used (as when designing and manufacturing electronic devices) in order to guarantee that each electrical circuit or electric current It is efficient, convenient and can be made available to the user safely.
The scope of this content reaches the field of medicine , since it facilitates procedures necessary to make diagnoses within the specialty of cardiology, to point out one possibility.
It is usual to consider the Lorentz force associated with an electric charge to define a magnetic field, which is produced by an electric charge generated by more than one moving electron.
History and equivalence of the coulomb
To add knowledge about the magnitude related to the electrical charge that accounts for the level of charge that, in one second, is carried with a current intensity of one ampere, it is necessary to collect data on the history and equivalence of the coulomb .
In 1861 it was proposed that the unit of electrical charge be named farad ( farad ) as a tribute to the British-born scientist Michael Faraday . Decades later, however, the farad was confirmed as a unit for calculating electrical capacity and the coulomb was fixed as a unit of electrical charge , whose name honors the figure of Charles-Augustin de Coulomb .
At that time, the members of the British Association for the Advancement of Science had taken care of defining the aforementioned farad , as well as the ohm and the volt , but the coulomb was missing. This is how, in 1881, the International Electrotechnical Commission ended up homologating it as a unit of electric charge , while the ampere (which in the past came to be specified based on the Lorentz force , an expression that refers to the force exerted by the electromagnetic field receiver of an electric current or a charged particle ) constituted it as a unit of electric current . Finally, he positioned the volt as a unit of electromotive force .
It cannot be overlooked that, despite being a unit derived from the International System of Units , it is common for the unit of electrical charge ampere-hour (Ah) to be used in electric batteries in order to reflect how much total charge it is capable of. to store each one of them. Nor should we ignore that, as it is too large to cover values of static charge , the coulomb is generally replaced by its corresponding submultiples: nanocoulombs , microcoulombs or millicoulombs . Example: a charge referring to static electricity arising from the friction of materials is expressed in a few microcoulombs .
The union and connection of different electrical components for the generation, transport and use of electrical energy is defined as an electrical circuit.
Importance of Coulomb's law
From both theory and practice, Coulomb's law is important since it allows us to understand electrical phenomena.
It also makes it clear that there are two varieties of electric charge : one defined as positive charge and another that is called negative charge . If they are different, that is, when a positive sign (+) is close to a negative sign (-), the phenomenon of attraction occurs; If there is equality in the charges (two positive or two negative signs), an act of repulsion is observed.
It is also interesting to draw a parallel between it (which focuses on electrical forces ) and the law of universal gravitation , which is linked to gravitational forces .