Name : Charles Agustin de CoulombNationality: FrenchBorn: June 14, 1736Died: August 23, 1806

Works: Coulomb's law Law of electrical repulsion Inverse torsion law Invented a sensitive instrument to measure the electrical forces involved

Frenchman born on June 14, 1736He attended Mazarin College in Paris before

his father’s poor business decisions strained the family’s finances resulting in Coulomb’s relocation to MontpelierCoulomb joined the

Academy of Sciences there and presented several papers to the organizationtopics in astronomy

and mathematics

Charles Augustin de Coulomb

Hoped to gain entry into the Royal School of Engineering

Decided to return to Paris for a short time, where he would have access to the better tutoring

1760 he began his formal studies at the institution completing them less than two years later

Back in Paris

After graduation, he embarked on a long career within the Military Engineering Corps.

In the army as a military engineer, he was drafted to the island of Martinique, in the West Indies

His duties forced him to make several moves over the subsequent decades.

Military Career

in the West Indies, he took part in the erection of Fort Bourbon. But the climate was then fatal; most of his comrades died of fever, and Coulomb, after a stay of three years, returned home with his health permanently injured.

Military Career

He submitted his first treatise to the Academy of Sciences in Paris in 1773

many more would follow on topics ranging from mathematical solutions of engineering problems to studies of friction, elasticity, electricity and magnetism.

In 1777 Coulomb was awarded part of the Academy’s grand prize for a paper discussing the magnetic compass

In 1781 he was sole recipient of the prize for a groundbreaking examination of friction.

Awards and Achievements

In 1784 he presented a paper to the Academy on the elasticity of wires under a twisting stress

he observed that a very feeble force was sufficient to twist a long thin wire through a large angle

This led to the invention of his well-known torsion balance

Awards and Achievements

It consists of a ‘ needle’ suspended by a fine wire, and screened from currents of air by a glass cover.

When the needle is deflected from its zero position through a certain angle by a disturbing force, it can be brought back to zero against the force by counter twisting the suspension wire

Torsion Balance

and the torsion of the wire becomes a measure of the disturbing force.

To this end a graduated scale is added, to indicate the turns of the counter-twist.

The rate of oscillation of the needle when deflected is also a means of calculating the disturbing force.

Torsion Balance

By presenting electrified bodies to the needle, which could itself be electrified, Coulomb discovered that the force of attraction or repulsion between two quantities of electricity was directly proportional to the quantities, and inversely proportional to the square of the distance between them

Torsion Balance

Similar to Isaac Newton’s inverse square law of gravitational force, Coulomb’s law states that the electric force between charged objects inversely depends upon the distance between the objects. That is the electric force decreases with the square of the distance between them.

Coulomb’s law

gravitation is influenced by the mass of the objects

Coulomb’s law depends upon the charge of the objects involved. When the objects in question are both

positively or both negatively charged, the forces between them are repulsive

but attractive forces arise between objects carrying opposing charges.

Newton vs. Coulomb

upon returning to Paris, became one of the first members of the newly formed French National Institute

His health grew progressively worse leading to his death on August 23, 1806. He was honored by the adoption of an

SI unit of electric charge bearing his name. The coulomb (C) is equivalent

to the charge transferred by a current of 1 ampere in 1 second.

Coulomb’s Later Years

www.biography.com › People www.brookscole.com/physics_d/student.../coulomb.html www.biografiasyvidas.com/biografia/.../coulomb. www.corrosion-doctors.org/Biographies/CoulombBio.htm www.electricalfacts.com/Neca/People/history/coulomb.shtml www-groups.dcs.st-nd.ac.uk/history/Biographies/Coulomb.htm www.hyperphysics.phy-astr.gsu.edu/hbase/electric/elefor.htmlwww. physics.bu.edu/~duffy/py106/Charge.html www.physics.org/explore-results-all.asp?q=coulomb&age=0www.scienceworld.wolfram.com/physics/CoulombsLaw.htmlwww.studyphysics.ca/30/coulomb.pdf

Sources