2.2 Michael faraday (1791-1867)

British physicist and chemist Michael Faraday, is best known for his discoveries of electromagnetic induction and of the laws of electrolysis.

Faraday was born on September 22, 1791, in Newington, Surrey, England. He was the son of a blacksmith and received little formal education. While apprenticed to a bookbinder in London, he read books on scientific subjects and experimented with electricity. In 1812 he attended a series of lectures given by the British chemist Sir Humphry Davy and forwarded the notes he took at these lectures to Davy, together with a request for employment. Davy employed Faraday as an assistant in his chemical laboratory at the Royal Institution and in 1813 took Faraday with him on an extended tour of Europe. Faraday was elected to the Royal Society in 182-1 and the following year was appointed director of the laboratory of the Royal Institution. In 1833 he succeeded Davy as professor of chemistry at the institution.

Faraday was the recipient of many scientific honors, including the Royal and Rum ford medals of the Royal Society ; the research that established him as the foremost experimental scientist of his day was, however, in the fields of electricity and magnetism. In 1821 he plotted the magnetic field around a conductor carrying an electric current; the existence of the magnetic field had first been observed by the Danish physicist Hans Christian Oersted in 1819. In 1831 Faraday followed this accomplishment with the discovery of electromagnetic induction and in the same year demonstrated the induction of one electric current by another.

During this same period of research he investigated the phenomena of electrolysis and discovered two fundamental laws: that the amount of chemical action produced by an electrical current in an electrolyte is proportional to the amount of electricity passing through the electrolyte; and that the amount of a substance deposited from an electrolyte by the action of a current is proportional to the chemical equivalent weight of the substance.

In experimenting with magnetism. Faraday made two discoveries of great importance; one was the existence of diamagnetism, and the other was the fiict that a magnetic Held has the power to rotate the plane of polarized light passing through certain types of glass.

2.3 James Maxwell

James Clerk Maxwell was one of the greatest scientist of the 19th century. He is best know for the formulation of the theory of electromagnetism and in making the connection between light and electromagnetic waves,

Maxwell was born in Edinburgh. Scotland in 1831. When he was only 14 years old, he published his firs! scientific paper on the mathematics of oval curves and ellipses.

Maxwell's early education took place at Edinburgh Academy and the University of Edinburgh. In 18S0 he went on to study at the University of Cambridge and, upon graduation from Cambridge, Maxwell became a professor of natural philosophy at Marischal College in Aberdeen until I860. He then moved to London to become a professor of natural philosophy and astronomy at King's College. In 1865_; he returned to Scotland to devote his time to research. In 1871 he accepted a position as the First professor of experimental physics at Cambridge where he set up the world famous Cavendish Laboratory in 1874.

Maxwell's particular gift was in applying mathematical reasoning in solving complex theoretical problems.

Maxwell began his work in electromagnetism by extending Michael Faraday's theories of electricity and magnetic lines of force. Using four equations, he described and quantified the relationships between electricity, magnetism and the propagation of electromagnetic waves. The equations are now known as Maxwell's Equations. Maxwell's Electromagnetic Equations are perfect examples of how mathematics can he used to provide relatively simple and elegant explanations of the complex mysteries of the universe. One of the first things that Maxwell did with the equations was to calculate the speed of an electromagnetic wave and found that Ihc speed of an electromagnetic wave was almost identical to the speed of light. Based on this discovery, he was the first to propose that light was an electromagnetic wave. Electricity, magnetism and light can now be understood as aspects of a single phenomenon: electromagnetic waves.

Maxwell also described the thermodynamic properties of gas molecules using statistical mechanics and also contributed to the development of color photography.