National Mathematics Day is observed on 22 December, the birth anniversary of which mathematician?

The correct answer is B, 1930. Chandrasekhara Venkata Raman received the Nobel Prize in Physics in 1930 for his work on the scattering of light and for the effect named after him, which he had demonstrated on 28 February 1928; he was the first Asian and the first person from a non-white country to win a Nobel Prize in any of the sciences. Option A, 1913, is the year Rabindranath Tagore won the Nobel Prize in Literature, the first Nobel of any kind to come to India, and candidates who remember only that an Indian won early in the century choose it. Option C, 1968, belongs to Har Gobind Khorana, who shared the prize in Physiology or Medicine for interpreting the genetic code. Option D, 1983, belongs to S. Chandrasekhar, Raman nephew, who shared the Physics prize for his work on the structure and evolution of stars. Keeping the four years 1930, 1968, 1983 and 2009 in order solves most questions in this chapter.

The correct answer is A, the Raman effect. C. V. Raman announced on 28 February 1928 that when a beam of light passes through a transparent medium a small fraction of it is scattered with a shifted wavelength, which carries information about the molecules of the medium; the Government of India fixed National Science Day on that anniversary in 1986. Option B is wrong; the Chandrasekhar limit, the greatest mass a white dwarf can hold, is a calculation of the early nineteen thirties and no national day is attached to it. Option C is wrong; Meghnad Saha ionisation equation, which explains the spectra of stars from their temperature and pressure, has no day of its own, important though the work is. Option D is wrong; the statistics worked out by Satyendra Nath Bose and extended by Einstein gave the boson its name but is likewise not marked by a day. The other days to remember are 22 December and 15 September.

The correct answer is B, Vikram Sarabhai. He founded the Physical Research Laboratory at Ahmedabad in 1947, convinced the government to set up the Indian National Committee for Space Research in 1962, picked Thumba near the magnetic equator for the first sounding rocket launch in November 1963, and led the organisation that became the Indian Space Research Organisation in 1969; the Vikram Sarabhai Space Centre at Thiruvananthapuram is named after him. Option A is wrong; Homi Bhabha is the father of the Indian nuclear programme, and swapping the two men is the commonest error in this chapter, though Bhabha did support the early space work. Option C is wrong; A. P. J. Abdul Kalam is the Missile Man, who directed the Satellite Launch Vehicle and the guided missile programme. Option D is wrong; Satish Dhawan headed ISRO from 1972 and the launch centre at Sriharikota is named after him, but he did not found the programme.

The correct answer is B, S. Chandrasekhar. Subrahmanyan Chandrasekhar showed, while still in his twenties, that a white dwarf heavier than about 1.44 times the mass of the Sun cannot be held up by the pressure of its degenerate electrons and must collapse further; the figure is called the Chandrasekhar limit, it underlies the modern account of neutron stars and black holes, and it brought him a share of the Nobel Prize in Physics in 1983. The Chandra X-ray Observatory is named for him. Option A is wrong; Meghnad Saha gave the ionisation equation that lets astronomers read the temperature of a star from its spectrum, a different and earlier contribution. Option C is wrong; Satyendra Nath Bose gave the quantum statistics after which bosons are named. Option D is wrong; Jagadish Chandra Bose worked on plant physiology and radio waves and had nothing to do with stellar structure, but the shared surname makes him a standard distractor.

The correct answer is B, the interpretation of the genetic code. Khorana shared the Nobel Prize in Physiology or Medicine in 1968 with Robert Holley and Marshall Nirenberg for showing how the sequence of nucleotides in nucleic acids specifies the amino acids of a protein; he later synthesised the first artificial gene, a landmark in molecular biology. He was born at Raipur in undivided Punjab and later became a citizen of the United States. Option A is wrong; alkaloid chemistry is associated with Asima Chatterjee, who worked on anti-epileptic and anti-malarial compounds. Option C is wrong; the structure and function of the ribosome brought Venkatraman Ramakrishnan a share of the Nobel Prize in Chemistry in 2009, four decades later. Option D is wrong; plant physiology is the field of Jagadish Chandra Bose, who built the crescograph to measure growth and showed that plants respond to stimuli.