ppt on Charles coulomb

1. Name : Charles Agustin de
Coulomb
Nationality: French
Born: June 14, 1736
Died: August 23, 1806
Works:
 Coulomb's law
 Law of electrical repulsion
 Inverse torsion law
 Invented a sensitive instrument to
measure the electrical forces
involved

2.  Frenchman born on June 14, 1736
 He attended Mazarin College in Paris before his
father’s poor business decisions strained the family’s
finances resulting in Coulomb’s relocation to
Montpelier
 Coulomb joined the
Academy of Sciences
there and presented
several papers to the
organization
 topics in astronomy
and mathematics

3.  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

4.  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.

5.  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.

6.  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.

7.  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

8.  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


9.  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.

10.  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

11.  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.

12.  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.

13.  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.

14.  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.html
 www. physics.bu.edu/~duffy/py106/Charge.html
 www.physics.org/explore-results-all.asp?q=coulomb&age=0
 www.scienceworld.wolfram.com/physics/CoulombsLaw.html
 www.studyphysics.ca/30/coulomb.pdf