Monday 26 November 2018

Great Scientist C.V.Raman

C. V. Raman  (Sir Chandrasekhara Raman)
In this Indian name, the name Chandrasekhara is a patronymic, not a family name, and the person should be referred to by the given name, Raman. Sir Chandrasekhara Venkata Raman, (7 November 1888 – 21 November 1970) was an Indian physicist, born in the former Madras Province, whose ground breaking work in the field of light scattering earned him the 1930 Nobel Prize for Physics. He discovered that, when light traverses a transparent material, some of the deflected light changes in wavelength. This phenomenon is now called Raman scattering and is the result of the Raman effect. In 1954, he was honoured with the highest civilian award in India, the Bharat Ratna.
 Family
Raman's maternal grandfather, Saptarshi Sastri, was a Sanskrit scholar who was learned in navya nyaya (modern logic). Raman's father initially taught in a school in Thiruvanaikaval, became a lecturer of mathematics and physics in Mrs. A.V. Narasimha Rao College, Vishakapatnam (then Vizagapatnam) in the Indian state of Andhra Pradesh, and later joined Presidency College in Madras (now Chennai). He was married on 6 May 1907 to Lokasundari Ammal (1892–1980). They had two sons, Chandrasekhar and radio-astronomer Radhakrishnan.
Raman was the paternal uncle of Subrahmanyan Chandrasekhar, who later won the Nobel Prize in Physics (1983) for his discovery of the Chandrasekhar limit in 1931 and for his subsequent work on the nuclear reactions necessary for stellar evolution.
 Early education
At an early age, Raman moved to the city of Visakhapatnam and studied at St. Aloysius Anglo-Indian High School. Raman passed his matriculation examination at the age of 11 and he passed his F.A. examination (equivalent to today's Intermediate exam 10+ 2) with a scholarship at the age of 13.
In 1902, Raman joined Presidency College in Madras where his father was a lecturer in mathematics and physics. In 1904 he passed his Bachelor of Arts (B.A.) examination: He stood first and won the gold medal in physics. In 1907 he gained his Master of Arts (M.A.) degree with the highest distinctions.

Achievements
In 1917, Raman resigned from his government service after he was appointed the first Palit Professor of Physics at the University of Calcutta. At the same time, he continued doing research at the Indian Association for the Cultivation of Science (IACS), Calcutta, where he became the Honorary Secretary. Raman used to refer to this period as the golden era of his career. Many students gathered around him at the IACS and the University of Calcutta.
During a voyage to Europe in 1921, Raman noticed the blue colour of glaciers and the Mediterranean sea. He was motivated to discover the reason for the blue colour. Raman carried out experiments regarding the scattering of light by water and transparent blocks of ice which explained the phenomenon.
There is an event that served as the inspiration of the Raman effect. On a December evening in 1927, Raman's student K. S. Krishnan (who later became the Director of the National Physical Laboratory) gave him the news that Professor Compton had won the Nobel Prize for his studies of the scattering of X-rays. This led Raman to theorize that if the Compton effect is applicable for X-rays, then it may be for light also, and to devise some experiments.
Raman employed monochromatic light from a mercury arc lamp which penetrated transparent material and was allowed to fall on a spectrograph to record its spectrum. He detected lines in the spectrum which he later called Raman lines. He presented his theory at a meeting of scientists in Bangalore on 16 March 1928.
 On 28 February 1928, Raman led experiments at the IACS with collaborators, including K. S. Krishnan, on the scattering of light, when he discovered what now is called the Raman effect and he won the Nobel Prize in Physics in 1930.
Books
For compact work, see: Scientific Papers of C. V. Raman, S. Ramaseshan (ed.).
Vol. 1 – Scattering of Light (Ed. S. Ramaseshan)
Vol. 2 – Acoustics
Vol. 3 – Optics
Vol. 4 – Optics of Minerals and Diamond
Vol. 5 – Physics of Crystals
Vol. 6 – Floral Colours and Visual Perception


Honours and awards
He was elected a Fellow of the Royal Society early in his career (1924) and knighted in 1929.
He won the Nobel Prize in Physics in 1930
 He was awarded the Franklin Medal in 1941
He was awarded the Bharat Ratna. in 1954
He was awarded the Lenin Peace Prize in 1957.
 The American Chemical Society and Indian Association for the Cultivation of Science recognised Raman's discovery as an International Historic Chemical Landmark in 1998
India celebrates National Science Day on 28 February of every year to commemorate the discovery of the Raman effect in 1928.
Achieve  of   Raman Research Papers
The Raman Research Institute, founded by Raman after his tenure at IISc, curates a collection of Raman's research papers, and articles on the web.

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