Definition of Faraday's Law

The law de Faraday relates two areas of science, the electricity and the magnetism. In this sense, said law affirms that the voltage induced is equivalent to the variation in time of a magnetic field. In other words, the electromotive force is equal to the variation of magnetic flux over time.

Understanding the operation of an electric motor from Faraday's law

If we have a magnet with two differentiated poles, they produce a magnetic field. When introducing the magnet into a coil, the variation of the magnetic flux over time produces a certain voltage, but if the magnet is kept away from the coil there is no alteration of the voltage. This phenomenon can be explained from Faraday's law, since a magnetic change that varies over time produces a voltage. This principle in turn explains the functioning of the electromagnetic induction that takes place in a motor.

How was Faraday's Law arrived at?

In 1820 the Danish scientist Hans Christian Oersted showed that a electric current

alter the needle of a compass. From this discovery Michael Faraday thought that if a current can alter a magnetic field, this means that a magnetic field could also generate an electric current.

For more than ten years Faraday tried to demonstrate his hypothesis He initially and finally succeeded by passing a magnet through the interior of a solenoid, which was connected to a galvanometer.

He observed that by rapidly moving the magnet the needle of the galvanometer also moved. This experiment resulted in parallel in a double technological advance: the development of generators and electric motors.

Other contributions

This British scientist is recognized as one of the great men of science of the 19th century. Apart from the law in which the relationship between electricity and magnetism is expressed, he also made other relevant contributions. He developed a method that allowed some gases to liquefy if they were subjected to a certain pressure. On the other hand, he promoted organic chemistry, since he was the discoverer of a new compound, benzene. He made important contributions to the further development of the electromagnetic theory of light (Faraday observed that a magnetic field can alter a beam of light).

Finally, he formulated the laws of electrolysis, which establish the relationship between chemical processes and electricity.

Michael Faraday was not a theoretical scientist like so many others, since throughout his life he gave talks and conferences to disseminate science among the youngest. His interventions were known as "Friday Evening Discourses" (talks on Friday afternoons).

Fotolia photos: Kmls / Archivist

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