ALSO KNOWN AS: - Sir Chandrasekhara Venkata Raman
NATIONALITY: - Indian
Famous Indian Men
RELIGION: - Hindu
BORN ON:-07 November 1888 AD
DIED AT AGE: - 82
SUN SIGN: - Scorpio.
BORN IN: - Tiruchirappalli, Madras Province
DIED ON: - 21 November 1970 AD
PLACE OF DEATH: - Bangalore, India
FATHER: - R. Chandrasekhara Iyer
MOTHER: -Parvati Amma
SPOUSE/PARTNER: - Lokasundari Ammal
DISCOVERIES / INVENTIONS: -Raman Effect
AWARDS: -Nobel Prize in Physics (1930)
Bharat Ratna (1954)
C.V. Raman
Abstract...Introduction.
Sir Chandrasekhara Venkata Raman, the Indian physicist who
made his motherland proud by becoming the first Indian to win the Nobel Prize
for Physics, was a scientist par excellence. He displayed a brilliant mind even
as a child and passed his matriculation examination at a much younger age as
compared to other students. As the son of a lecturer in mathematics and
physics, the young Raman was exposed to an academic environment from the very
beginning. A topper throughout his academic days, he was deeply interested in
research; in fact he began his research work on optics and acoustics even while
he was a student. Even though he started his career as a Deputy Accountant
General, still he could not keep away from research, often staying up whole
nights to discover new things in the field of physics. He was intrigued by the
blue colour of glaciers and the Mediterranean sea and wanted to unravel the
mystery that why water, a colorless liquid, appeared blue to the eyes. Thus
began a series of experiments on the scattering of light which ultimately led
to what came to be known as the ‘Raman Effect’ for which he won the Nobel Prize
in Physics.
Childhood & Early Life of C.V.Raman
called “Bachpan”
He was born near a small village in Tiruchirapalli to R.
Chandrasekhara Iyer and Parvathi Ammal. His father, initially a school teacher,
became a lecturer in mathematics and physics in a college in Vishakhapatnam.
Raman studied in St. Aloysius Anglo-Indian High School at Vishakhapatnam.
He was a brilliant student and passed his matriculation examination when he was
just 11. At the age of 13 he passed his F.A. examination (equivalent to today’s
intermediate examination) with a scholarship.
He joined the Presidency College in Madras in 1902 and
received his B.A. in physics in 1904. He topped the exams and won a gold medal.
Three years later, he earned his M.A. degree in 1907.
Raman’s Career….throughout his life.
Though he was deeply interested in science, he appeared for
the Financial Civil Service (FCS) examination at the insistence of his father.
He topped the examination and went to Calcutta in 1907 to join the Indian
Finance Department as Assistant Accountant General.
Still his heart was in scientific research and he began
conducting research at the Indian Association for Cultivation of Sciences
during his free time. His job was very hectic, yet he was so dedicated towards
science that he often spent nights at research.
Even though the facilities available at the association were
very limited, it did not deter Raman at all who went on to publish his findings
in leading international journals like ‘Nature’, ‘The Philosophical Magazine’,
and ‘Physics Review’. During this time, his research was basically in the areas
of vibrations and acoustics.
In 1917, he got the opportunity to join the University of
Calcutta as the first Palit Professor of Physics. Raman happily resigned from
his government post to take up this position though the new job paid much less
than the previous one. Such was his dedication to science.
In 1919, he was made the Honorary Secretary of the Indian
Association for the Cultivation of Science, a post he held till 1933. He was
very popular and many students gathered around him, attracted by his immense
knowledge of science.
During the late 1920s he experimented on the scattering of
light by observing the behavior of monochromatic light which penetrated
transparent materials and fell on a spectrograph. This led to the discovery of
what came to be known as ‘Raman Effect’ which he presented at a meeting of
scientists in 1928.
He was invited by the Indian Institute of Science (IISc)
Bangalore to become its Director. He accepted the post in 1933, becoming the
first Indian to hold this post. He served as the director till 1937 though he
continued as the head of the Physics Department till 1948.
In 1948 he established the Raman Research Institute (RRI) in
Bangalore for conducting scientific research in different fields of physics. He
continued with his research in the institute till his death.
Raman’s …Highlights of his Major
Works.
He is best known for discovering the ‘Raman Effect’, or the
inelastic scattering of a photon. He showed through experimentation that when
light traverses a transparent material, some of the deflected light changes in
wavelength. This was a ground breaking discovery in early 20th century physics.
The Raman Effect
Raman and Rayleigh Scattering
Lord Rayleigh, who had believed the teenage Raman’s papers
were the work of a professor, had been one of the great physicists of his day.
He had won the 1904 Nobel Prize in Physics.
His importance to Raman’s story is that Rayleigh had been
the first to explain why the sky is blue. He had then explained the sea’s color
by saying it was simply a reflection of the sky’s color.
One day, in the summer of 1921, Raman was on the deck of a
ship in the Mediterranean Sea en route to the Congress of Universities of the
British Empire at Oxford. He looked at the beautiful blue color of the
Mediterranean Sea and began to doubt Rayleigh’s explanation of its color.
Rayleigh had correctly explained that the sky looks blue
because of a phenomenon now called Rayleigh scattering.
Rayleigh scattering
An approximate representation of Rayleigh scattering in
Earth’s atmosphere.
If Earth had no atmosphere, anyone who happened to be around
in such circumstances would see a white sun and a black sky. However, this is
not what we see, because sunlight interacts with the gases in Earth’s
atmosphere.
Rather than coming straight to our eyes from the sun,
sunlight is scattered in all directions by the atmosphere. Blue light is
scattered most, meaning that it comes to our eyes from everywhere in the sky,
therefore the sky looks blue. Yellow and red light are scattered least, so we
usually see a yellow sun, and sometimes a red sun.
Rayleigh scattering is elastic. This means that photons of
light lose no energy when they interact with gas molecules. The light,
therefore, stays the same color.
Raman Discovers that the Sea Scatters
Light
When he sailed back to India in September 1921 Raman, an
indefatigable scientist, had with him some simple physics apparatus: a prism, a
miniature spectroscope, and a diffraction grating. He used these to study the
sky and the sea and concluded that the sea was scattering light.
Hence when Rayleigh said the sea’s color is simply a
reflection of the sky’s color, he was not wholly correct. Raman reported his
findings in a letter to the journal Nature.
When he returned to his laboratory, Raman and his students
began an exhaustive program of research into light scattering.
Compton Demonstrates Inelastic
Scattering
In 1923 Arthur Compton in St. Louis, USA published exciting
new work showing that X-rays can lose energy when they interact with electrons.
The X-rays donate some of their energy to electrons, then move on carrying less
energy. In other words, Compton demonstrated that inelastic scattering is
possible.
Compton received the 1927 Nobel Prize in Physics for this
discovery, which became known as the Compton effect.
The significance of the Compton effect is that in classical
electrodynamics the scattering of X-rays and other electromagnetic radiation
must always be elastic. Compton’s results agreed with quantum theory rather
than classical theory.
The inelastic scattering discovered by Compton caused X-ray
wavelengths to increase. If inelastic scattering and hence longer wavelengths
were possible for visible light, then the light’s color would change.
The Raman Effect
Raman and his students continued researching light
scattering in gases, liquids and solids.
They used monochromatic light – sunlight that had been
filtered to leave only a single color – and found that a variety of different
liquids – sixty of them – did indeed change the color of the light. They first
observed this in April 1923, but very weakly.
In 1927 they found a particularly strong color change in
light scattered by glycerol (then called glycerine):
Raman’s team observed the effect in gases, crystals and
glass. The effect might have been mistaken for fluorescence, another phenomenon
in which light has its color changed, but in Raman’s work the light scattered
by liquids was polarized, which ruled out fluorescence.
What came to be known as the Raman effect – a color change
accompanied by polarization – had never been seen before. The inelastic
scattering at its heart was a further, very strong confirmation, of quantum
theory.
The Raman effect is a very small effect compared with
Rayleigh scattering. Only about 1 in ten million photons undergoes inelastic
scattering.
Raman and his colleague K.S. Krishnan reported their
discovery in March 1928 in Nature.
Raman was awarded the 1930 Nobel Prize in Physics for “work
on the scattering of light and for the discovery of the effect named after
him.”
Raman Spectroscopy
Raman showed that the energy of photons scattered
inelastically serves as a ‘fingerprint’ for the substance the light is
scattered from. As a result of this, Raman spectroscopy is now commonly used in
chemical laboratories all over the world to identify substances. It is also
used in medicine to investigate living cells and tissues – even detecting
cancers – without causing harm. Laser light rather than sunlight is used as the
source of photons.
The Photon’s Spin
In 1932 Raman and his student Suri Bhagavantam discovered
that photons of light carry angular momentum – in quantum terms, photons
possess a property called spin.
Light and other forms of electromagnetic radiation pass
their angular momentum on to atoms that absorb them.
Awards & Achievements
He won the 1930 Nobel Prize in Physics "for his work on
the scattering of light and for the discovery of the Raman Effect",
becoming the first Indian to win a Nobel Prize in the sciences.
He was honored with the Bharat Ratna, India’s highest
civilian award, in 1954 in recognition of his invaluable contributions to the
field of science.
Personal Life & Legacy
He married Lokasundari Ammal in 1907 and had two sons with
her—Chandrasekhar and Radhakrishnan.
He lived a long and productive life and was active till the
very end. He died in 1970 at the age of 82.
Trivia
This great scientist was the paternal uncle of another
excellent scientist and Nobel laureate, Subrahmanyan Chandrasekhar.
