Theory Snapshot

Science is the story of questions asked and the people who answered them. From the falling apple that sparked Newton’s gravity to the mysterious compass that guided Einstein toward relativity, every law, unit and symbol we use today was once someone’s lifetime obsession. Railway exams expect you to recall the “who gave what” linkage—mainly physicists, chemists and biologists whose discoveries changed transport, health, energy and communication.

The examiner’s favourite 30-odd names can be grouped into (a) Laws & Units—Newton, Joule, Ohm, Watt, Roentgen, Curie; (b) Evolution & Genetics—Darwin, Lamarck, Mendel, Watson-Crick; (c) Micro-world & Disease—Pasteur, Koch, Fleming, Jenner; (d) Modern Physics—Planck, Einstein, Rutherford, Bohr; (e) Space & Satellite—Kepler, Galileo, Kalam, S. Chandrasekhar. Link each scientist to one keyword (law, particle, theory, vaccine, satellite) and you are 90 % done. The remaining 10 % is remembering nationality, year and Nobel Prize tags.

Practice MCQs

1. Who gave the three laws of planetary motion?

• A. Galileo Galilei
• B. Johannes Kepler
• C. Tycho Brahe
• D. Isaac Newton

2. The unit of electric resistance is named after which scientist?

• A. Alessandro Volta
• B. André-Marie Ampère
• C. Georg Simon Ohm
• D. Michael Faraday

3. “Principia Mathematica” was written by

• A. Kepler
• B. Newton
• C. Einstein
• D. Galileo

4. Penicillin was discovered by

• A. Robert Koch
• B. Louis Pasteur
• C. Alexander Fleming
• D. Joseph Lister

5. The small-pox vaccine was first developed by

• A. Edward Jenner
• B. Jonas Salk
• C. Albert Sabin
• D. Ronald Ross

6. “Origin of Species” was published in

• A. 1759
• B. 1809
• C. 1859
• D. 1909

7. The atomic nucleus was discovered by

• A. J. J. Thomson
• B. Ernest Rutherford
• C. Niels Bohr
• D. James Chadwick

8. The neutron was discovered by

• A. Rutherford
• B. Chadwick
• C. Fermi
• D. Pauli

9. Who explained photoelectric effect using quantum concept?

• A. Planck
• B. Bohr
• C. Einstein
• D. Heisenberg

10. The triple-helix model of DNA was wrongly proposed by

• A. Watson & Crick
• B. Linus Pauling
• C. Rosalind Franklin
• D. Erwin Chargaff

11. “One gene-one enzyme” hypothesis was given by

• A. Beadle & Tatum
• B. Jacob & Monod
• C. Hershey & Chase
• D. Avery & McLeod

12. The law of inheritance independently rediscovered by

• A. Hugo de Vries, Correns & Tschermak
• B. Lamarck, Darwin, Wallace
• C. Haeckel, Weismann, Mendel
• D. Morgan, Sturtevant, Bridges

13. The term “radioactivity” was coined by

• A. Henri Becquerel
• B. Pierre Curie
• C. Marie Curie
• D. Ernest Rutherford

14. Which Indian physicist is known for “Boson”?

• A. C. V. Raman
• B. Meghnad Saha
• C. Satyendra Nath Bose
• D. Homi Bhabha

15. The missile-man of India is

• A. Vikram Sarabhai
• B. A. P. J. Abdul Kalam
• C. R. A. Mashelkar
• D. K. Radhakrishnan

16. The unit of activity of radioactive substance is

• A. Gray
• B. Sievert
• C. Becquerel
• D. Curie

17. Who gave the first accurate measurement of speed of light?

• A. Roemer
• B. Fizeau
• C. Foucault
• D. Michelson

18. “Cosmic rays” coined & studied extensively by

• A. Robert Millikan
• B. Victor Hess
• C. C. T. R. Wilson
• D. Karl Jansky

19. The principle of rocket motion is based on

• A. Newton’s 1st law
• B. Newton’s 2nd law
• C. Newton’s 3rd law
• D. Archimedes principle

20. Which scientist introduced the concept of “isotopes”?

• A. Soddy
• B. Aston
• C. Moseley
• D. Urey

21. “Principles of Geology” was written by

• A. Charles Lyell
• B. Alfred Wegener
• C. Arthur Holmes
• D. James Hutton

22. The first artificial transmutation of an element was done by

• A. Rutherford
• B. Irene Joliot-Curie
• C. Otto Hahn
• D. Ernest Lawrence

23. “One gene-one polypeptide” revision was necessitated because of discovery of

• A. Exons
• B. Introns
• C. Split genes
• D. All of the above

24. Which duo shared the 2020 Chemistry Nobel for CRISPR-Cas9?

• A. Doudna & Charpentier
• B. Zhang & Church
• C. Banerjee & Mukherjee
• D. Sharp & Roberts

25. The Chandrasekhar limit (1.4 M☉) relates to

• A. Maximum mass of white dwarf
• B. Minimum mass of neutron star
• C. Mass of black hole
• D. Mass of brown dwarf

Quick-fire Shortcuts

1. “NO E=mc² without PEM” – Planck (P), Einstein (E), Millikan (M) → Quantum & Photoelectric.
2. “Rutherford = Nucleus, Chadwick = Neutron, Bohr = Orbits” – 1-2-3 in order.
3. “Medals on the Chest” – Mendel, Darwin, Pasteur, Koch, Fleming → Disease & Evolution.
4. “Indian Nobel trio” – Raman (Physics), Chandrasekhar (Physics), Khorana (Medicine).
5. Unit = Scientist – °C (Celsius), J (Joule), W (Watt), N (Newton), Ω (Ohm), Bq (Becquerel).
6. Year shortcut – 1687 Principia, 1859 Origin, 1905 Miracle, 1911 Nucleus, 1953 DNA.
7. Railway GK favourite – Kalam → SLV-3, Agni, Prithvi; Vikram Sarabhai → ISRO founder.

Tip: Make a 5×6 table (Scientists vs. Discovery, Unit, Year, Nobel, Country) and glance daily; 70 % questions will fall within these 30 cells.