The great scientist CV Raman

C. V. Raman: Great Indian Scientist and his Famous Effect

Sir C. V. Raman
Credit – Nobel Foundation (1930) (License – Public Domain). Source – http://nobelprize.org/nobel_prizes/physics/laureates/1930/raman-bio.html

A Short Biography of C. V. Raman

Chandrashekara Venkata Raman was born at Tiruchirapalli in Tamil Nadu on 7th November 1888. His parents were Chandrashekara Iyyer and Parvathi Ammal, whose family had been pursuing the profession of agriculture and were of moderate means.

His father initially started teaching at a local English High School and later accepted a post of lecturer in Physics and Mathematics at Mrs. AVN College, Vizagapatam, today known as Vishakapatnam, on the East coast of India situated in the Andhra Pradesh state.

He moved with his parents to Vizagapatam when he was four years old. The next ten years of his life were spent in Vishakapatnam, where he studied for eight years in high school and two years in college. He passed the Intermediate examination and joined Madras Presidency College in 1903.

He passed the BA examination in 1904, winning the first rank and a Gold Medal in Physics. He also cleared the MA degree examination in 1907, with first-class and record marks. Raman had a keen interest in scientific research and the urge to discover since he was young.

He was considered an excellent student with an inquiring and restless mind and sharp intellect. However, due to the circumstances in India at that time, he applied for a job at Indian Administrative Services. While serving in Calcutta, by chance he noticed the signboard of the Indian Association for the Cultivation of Science.

He later worked in this institution for many years and conducted many experiments over the course of many years which led him to the discovery of the Raman Effect. While in Government service, he contributed many original papers in many branches of Physics to journals like Nature, Philosophical Magazine, and Physical Review.

He left the Government service in 1917 and joined the University of Calcutta as a Palit Professor of Physics.  In 1919, he was appointed as the Honorary Secretary of the Indian Association for the Cultivation of Science. He made a brief visit to Europe in 1921 as a delegate to the Universities Congress at Oxford.

It was during this voyage that he was intrigued by the blue color of the Mediterranean Sea. He was elected as a Fellow of the Royal Society in 1924. In 1926 he established the Indian Journal of Physics. He joined the Indian Institute of Science in Bangalore in 1933 as its first Indian director. He founded the Indian Academy of Sciences in 1934.

He founded a company named Travancore Chemicals and Manufacturing Co. Ltd in 1943 with his former student Panchapakesa Krishnamurti. He was appointed as the first National Professor by the new government of Independent India. Raman retired from the Indian Institute of Science in 1948. He established Raman Research Institute in Bangalore in 1949. He served as its director and worked there until his death in 1970.


What are the scientific contributions of C. V. Raman?

Did C. V. Raman investigate the physics of Indian musical instruments?

CV Raman early in his career was interested in understanding the physics of musical sounds. He was inspired by Hermann von Helmholtz’s book, The Sensations of Tone. He derived the theory of transverse vibration of bowed string instruments on the basis of superposition of velocities. He studied the wolf tone in violins and cellos.

He studied the acoustics of Indian musical instruments such as the tabla and the mridangam. He studied Kaufmann’s theory on vibrations of the pianoforte string. He even studied the unusual sound effects in the Whispering Gallery of the dome of St. Paul’s Cathedral in London. His work on acoustics was an important prelude to his later works on optics and quantum mechanics.


What are C. V. Raman’s contributions in explaining the scattering of light?

Blue Color of the Sea.
Image Credit – Photo by Ricardo Esquivel from Pexels, Source – https://www.pexels.com/photo/blue-and-white-abstract-painting-1802268/, Licensing – Free to use

Raman started to work on the phenomenon of scattering of light in 1919. When he was sailing in the Mediterranean Sea, he was intrigued by the blue color of the sea. There were several hypotheses put forward for the color of the sea such as Lord Rayleigh’s in 1910, who stated that the much-admired dark blue of the deep sea has nothing to do with the color of the water, but is simply the blue of the sky seen by reflection.

Raman, true to his scientific spirit studied the seawater using a pocket-sized spectroscope and a Nicol prism. The Nicol prism made it possible to view the seawater without the influence of sunlight reflected by the surface.

Raman found out that the sea appears to be even bluer than predicted by Rayleigh. As soon as he returned to India, he published an article in Nature called “The color of the sea” in which he said that Rayleigh’s prediction is questionable by a simple mode of observation.

Raman predicted that just as in the case of the blue color of the sky which is explained by Rayleigh scattering, the observed luminosity and also its color is dependent on molecular diffraction. In 1925, Raman’s Research Associate in his laboratory found the theoretical background for the existence of an additional scattering line beside the usual polarized elastic scattering when light scatters through a liquid.

His research student, Krishnan discovered in January 1928 that no matter what kind of pure liquid was used, the experiment always produced polarized fluorescence within the visible spectrum of light. They called the phenomenon “modified scattering’ with reference to the Compton effect which they considered to be unmodified scattering.

Raman and Krishnan obtained the spectra of the modified scattering separate from the incident light on 28 February 1928. This day of the discovery of the Raman effect is celebrated as National Science Day in our country. The Raman effect was one of the earliest proofs of the quantum nature of light. CV Raman was awarded Nobel Prize in Physics in 1930 for this work.


What are some of the other important contributions of C. V. Raman?

The 1930 Nobel Prize Winners. (from left CV Raman (physics), Hans Fischer (chemistry), Karl Landsteiner (medicine), and Sinclair Lewis (literature).) Image Credit – Unknown, Source – https://app.tt.se/bild/q=Karl%20Landsteiner, Licensing – Public Domain

In 1932, Raman along with Suri Bhagavantam determined the spin of photons. In 1935, Raman along with his student Nagendra Nath gave the theoretical explanation for the acousto-optic effect which is the light scattering by sound waves.

Raman carried out experimental and theoretical studies on the diffraction of light by acoustic waves of ultrasonic and hypersonic frequencies. He also worked on the effects produced by X-rays on infrared vibrations in crystals exposed to light. Raman was very interested in studying the spectroscopic behavior of crystals. He was also interested in the optics of colloids.


References

  1. Singh, Rajinder (2008). “80 Years Ago – the Discovery of the Raman Effect at the Indian Association for the Cultivation of Science, Kolkata, India” (PDF). Indian Journal of Physics82: 987–1001.
  2. Raman, C.V. (1919). “LVI. The scattering of light in the refractive media of the eye”The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science38 (227): 568–572. doi:10.1080/14786441108635985.
  3. Anon. (2009). “This Month in Physics History: February 1928: Raman scattering discovered”APS News12 (2): online.
  4. Rayleigh, J.W.S. (1910). “Colours of Sea and Sky”Nature83 (2106): 48–50. Bibcode:1910Natur..83…48.doi:10.1038/083048a0
  5. Banerjee, Somaditya (2014). “C. V. Raman and Colonial Physics: Acoustics and the Quantum”. Physics in Perspective16 (2): 146–178. Bibcode:2014PhP….16..146Bdoi:10.1007/s00016-014-0134-8S2CID 121952683
  6. Raman, C.V. (1916). “XLIII. On the “wolf-note” in bowed stringed instruments”. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science32 (190): 391–395. doi:10.1080/14786441608635584.
  7. Raman, C. V. (1916). “On the “Wolf-note” of the Violin and ‘Cello”Nature97 (2435): 362–363. Bibcode:1916Natur..97..362Rdoi:10.1038/097362a0S2CID 3966106
  8. Raman, C.V. (1918). “On the mechanical theory of the vibrations of bowed strings and of musical instruments of the violin family, with experimental verification of the results-Part I” (PDF). Bulletin of the Indian Association for the Cultivation of Science15: 1–158.
  9. Raman, C.V. (1921). “On some Indian stringed instruments” (PDF). Proceedings of the Indian Association for the Cultivation of Science7: 29–33.
  10. Raman, C. V.; Kumar, Sivakali (1920). “Musical Drums with Harmonic Overtones”Nature104 (2620): 500. Bibcode:1920Natur.104..500Rdoi:10.1038/104500a0S2CID 4159476.
  11. Raman, C.V.; Banerji, B. (1920). “On Kaufmann’s theory of the impact of the pianoforte hammer”Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character97 (682): 99-110. Bibcode:1920RSPSA..97…99Rdoi:10.1098/rspa.1920.0016.
  12. Raman, C. V.; Sutherland, G. A. (1921). “Whispering-Gallery Phenomena at St. Paul’s Cathedral”. Nature108 (2706): 42. Bibcode:1921Natur.108…42Rdoi:10.1038/108042a0S2CID 4126913.
  13. Raman, C.V. (1922). “On whispering galleries” (PDF). Bulletin of the Indian Association for the Cultivation of Science7: 159–172.
  14. Rayleigh, Lord (1899). “XXXIV. On the transmission of light through an atmosphere containing small particles in suspension, and on the origin of the blue of the sky”The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science47 (287): 375–384. doi:10.1080/14786449908621276.
  15. Raman, C. V. (1921). “The Colour of the Sea”. Nature108 (2716): 367. Bibcode:1921Natur.108..367Rdoi:10.1038/108367a0S2CID 4064467.
  16. Raman, C.V. (1922). “On the molecular scattering of light in water and the colour of the sea”Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character101 (708): 64–80. Bibcode:1922RSPSA.101…64Rdoi:10.1098/rspa.1922.0025.
  17. Krishnan, K.S. (1925). “LXXV. On the molecular scattering of light in liquids”. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science50 (298): 697–715. doi:10.1080/14786442508634789.
  18. Compton, Arthur H. (May 1923). “A Quantum Theory of the Scattering of X-Rays by Light Elements”Physical Review21 (5): 483-502. Bibcode:1923PhRv…21..483Cdoi:10.1103/PhysRev.21.483.
  19. Raman, C. V.; Krishnan, K. S. (1928). “A new type of secondary radiation”. Nature121 (3048): 501–502. Bibcode:1928Natur.121..501Rdoi:10.1038/121501c0S2CID 4128161.
  20. Raman, C. V.; Bhagavantam, S. (1932). “Experimental Proof of the Spin of the Photon”Nature129 (3244): 22–23. Bibcode:1932Natur.129…22Rdoi:10.1038/129022a0hdl:10821/664S2CID 4064852.
  21. C. V. Raman, N. S. Nagendra Nath, “The diffraction of light by high-frequency sound waves. Part I”Proc. Ind. Acad. Sci., 1935

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