Q100. Consider the following inventor–invention pairs:
1. Flying shuttle loom — John Kay;
2. Water frame — James Hargreaves;
3. Spinning jenny — Richard Arkwright.
How many pairs are correctly matched?
[UPSC NDA (I) – 2026]
(A) Only one
(B) Only two
(C) All three
(D) None
Answer: (A) Only one
Explanation: John Kay developed the flying shuttle, improving weaving speed. The water frame is associated with Richard Arkwright, while James Hargreaves invented the spinning jenny. Therefore, only the first pairing is correct; the other two inventors have been interchanged.
Q99. Who is credited with the discovery of the electron?
[RRB NTPC Graduate – 2026]
(A) Marie Curie
(B) Ernest Rutherford
(C) Albert Einstein
(D) J. J. Thomson
Answer: (D) J. J. Thomson
Explanation: In 1897, J. J. Thomson investigated cathode rays and demonstrated the existence of negatively charged particles smaller than atoms. These became known as electrons. His work overturned the idea that atoms were indivisible and laid the groundwork for modern atomic models.
Q98. Which pioneering molecular biologist co-discovered the double-helix structure of DNA with Francis Crick?
[RRB Group D – 2026]
(A) James D. Watson
(B) Rosalind Franklin
(C) Maurice Wilkins
(D) Francis Crick
Answer: (A) James D. Watson
Explanation: James Watson and Francis Crick proposed the double-helix model in 1953. Rosalind Franklin’s X-ray diffraction results and Maurice Wilkins’s research provided crucial evidence. The model explained how complementary DNA strands could store and faithfully replicate hereditary information.
Q97. Which material did Robert Hooke observe when he discovered and named cells?
[RRB Group D – 2026]
(A) A thin slice of cork
(B) Human cheek cells
(C) Onion peel
(D) Leaf surface
Answer: (A) A thin slice of cork
Explanation: Robert Hooke examined thin cork sections under a microscope in 1665. The tiny compartments reminded him of monks’ rooms, which he called cells. He was observing dead plant cell walls rather than living cellular contents.
Q96. Which computing pioneer is credited with the concept of the stored-program computer architecture?
[RRB NTPC Undergraduate – 2026]
(A) Alan Turing
(B) Charles Babbage
(C) Blaise Pascal
(D) John von Neumann
Answer: (D) John von Neumann
Explanation: John von Neumann’s influential 1945 report described a computer design in which instructions and data reside in memory. Although others contributed to stored-program computing, the model is commonly called von Neumann architecture and remains central to computer organization.
Q95. The fourth generation of computers began with the invention of which key component?
[RRB NTPC Graduate – 2026]
(A) Microprocessor chip
(B) Transistor device
(C) ENIAC computer
(D) Tabulating machine
Answer: (A) Microprocessor chip
Explanation: Fourth-generation computers emerged when processors were integrated onto single semiconductor chips. Microprocessors helped reduce size, power consumption and cost while increasing processing capability. Transistors characterized the second generation, whereas integrated circuits defined the third generation.
Q94. Rutherford’s gold-foil experiment established the presence of which part of an atom?
[RRB Group D – 2026]
(A) Nucleus
(B) Protons
(C) Electrons
(D) Neutrons
Answer: (A) Nucleus
Explanation: Ernest Rutherford’s alpha-particle scattering experiment showed that most of an atom is empty space and that nearly all its positive charge and mass are concentrated in a tiny nucleus. Later discoveries clarified the particles composing that nucleus.
Q93. Who is credited with establishing the law of conservation of mass?
[RRB NTPC Undergraduate – 2026]
(A) Joseph Priestley
(B) Antoine Lavoisier
(C) John Dalton
(D) Dmitri Mendeleev
Answer: (B) Antoine Lavoisier
Explanation: Antoine Lavoisier used careful quantitative experiments to show that matter is conserved during ordinary chemical reactions. His work helped transform chemistry into a measurement-based science. Conservation of mass applies to closed chemical systems, where reactant and product masses balance.
Q92. Who discovered the antibacterial properties of Penicillium mould?
[RRB NTPC Graduate – 2025]
(A) Paul Ehrlich
(B) Alexander Fleming
(C) Antonie van Leeuwenhoek
(D) Marie Curie
Answer: (B) Alexander Fleming
Explanation: Alexander Fleming noticed in 1928 that a Penicillium mould inhibited bacterial growth on a culture plate. His findings were reported in 1929. Howard Florey, Ernst Chain and colleagues later helped turn penicillin into a practical antibiotic treatment.
Q91. Who invented the reflecting telescope?
[RPF Constable – 2025]
(A) Johannes Kepler
(B) Isaac Newton
(C) Christiaan Huygens
(D) Galileo Galilei
Answer: (B) Isaac Newton
Explanation: Isaac Newton constructed an early practical reflecting telescope in 1668. Unlike refracting telescopes, which use lenses, his design used mirrors to collect and focus light. This reduced chromatic aberration, a colour-fringing problem found in many early lens-based instruments.
Q90. Who first stated the zeroth law of thermodynamics explicitly in the twentieth century?
[RRB NTPC Undergraduate – 2025]
(A) Hugh L. Callendar
(B) James P. Espy
(C) Rudolf Clausius
(D) Ralph H. Fowler
Answer: (D) Ralph H. Fowler
Explanation: Ralph H. Fowler is associated with formulating and naming the zeroth law in the 1930s. The law says that systems individually in thermal equilibrium with a third system are in equilibrium with each other, providing a foundation for temperature measurement.
Q89. What was Gregor Mendel’s most important contribution to genetics?
[RRB Group D – 2025]
(A) Theory of evolution
(B) Discovery of the DNA structure
(C) Inheritance of acquired characteristics
(D) Laws of inheritance
Answer: (D) Laws of inheritance
Explanation: Through pea-plant breeding experiments, Gregor Mendel identified regular patterns in how traits pass between generations. His principles of segregation and independent assortment became central to classical genetics, although the molecular basis of genes was discovered much later.
Q88. Who discovered the laws governing levers and investigated the principles of pulleys?
[SSC CGL Tier-II (2024 cycle) – 2025]
(A) Archimedes
(B) Pythagoras
(C) Eudoxus
(D) Democritus
Answer: (A) Archimedes
Explanation: Archimedes analysed equilibrium in levers and formulated the principle that turning effects depend on force and distance from a fulcrum. His work on simple machines established mechanical ideas still used in engineering, lifting equipment and physics instruction.
Q87. What was the name of the instrument for measuring wind speed that dates back to the fifteenth century?
[SSC CGL – 2024]
(A) Transmissometer
(B) Dropsonde
(C) Anemometer
(D) Ceiling projector
Answer: (C) Anemometer
Explanation: An anemometer measures wind speed. Early descriptions of wind-measuring instruments date to Leon Battista Alberti around 1450, although designs evolved greatly afterwards. Modern anemometers may use rotating cups, propellers, heated wires or ultrasonic sensors for measurements.
Q86. Which scientist proposed that electrons can move in certain stable atomic orbits without continuously radiating energy?
[UPSC NDA – 2024]
(A) Ernest Rutherford
(B) J. J. Thomson
(C) Niels Bohr
(D) Albert Einstein
Answer: (C) Niels Bohr
Explanation: Niels Bohr’s 1913 atomic model introduced permitted electron orbits or energy levels. Electrons emit or absorb light when transitioning between levels, rather than losing energy continuously in a stationary state. This addressed an important weakness in Rutherford’s earlier model.
Q85. Which statement correctly describes James Watt’s contribution to the Industrial Revolution?
[UPSC NDA – 2024]
(A) Thomas Savery invented the astrolabe
(B) Thomas Newcomen invented synthetic dyes
(C) James Watt improved the steam engine so it could power factories, not merely pump water
(D) Matthew Boulton discovered the refining of gold
Answer: (C) James Watt improved the steam engine so it could power factories, not merely pump water
Explanation: James Watt improved steam-engine efficiency, notably through the separate condenser, making broader industrial use economical. Earlier engines were largely employed to pump water from mines. Watt’s refinements supported factory power and machinery during the Industrial Revolution.
Q84. Who experimentally demonstrated electromagnetic waves, supporting Maxwell’s theory, by producing and detecting radio waves in the 1880s?
[SSC CHSL – 2024]
(A) Heinrich Hertz
(B) William Hopkins
(C) Guglielmo Marconi
(D) Michael Faraday
Answer: (A) Heinrich Hertz
Explanation: Heinrich Hertz generated and detected electromagnetic waves in laboratory experiments during the late 1880s. His observations confirmed James Clerk Maxwell’s predictions that changing electric and magnetic fields propagate as waves. The unit of frequency, hertz, honours him.
Q83. Who discovered the principle that an immersed body experiences an upward force equal to the weight of displaced fluid?
[SSC CPO – 2024]
(A) Niels Bohr
(B) Isaac Newton
(C) Galileo Galilei
(D) Archimedes
Answer: (D) Archimedes
Explanation: Archimedes’ principle explains buoyancy as the upward force exerted by a fluid on an immersed object. This force equals the weight of fluid displaced. The principle helps determine whether objects float, sink or remain suspended in liquids.
Q82. Who discovered the black reaction, a staining method that reveals the structure of entire neurons?
[SSC JE (Civil) – 2024]
(A) Robert Remak
(B) Albert Kölliker
(C) Camillo Golgi
(D) Jacques Loeb
Answer: (C) Camillo Golgi
Explanation: Camillo Golgi developed a silver-chromate staining technique in 1873 that made individual nerve cells visible against a comparatively clear background. This black reaction revolutionized microscopic study of neurons and enabled later advances in understanding nervous-system structure.
Q81. Who shared the 2005 Nobel Prize in Physiology or Medicine with Barry Marshall for discovering the bacterium associated with gastric ulcers?
[SSC JE (Electrical) – 2024]
(A) Jean-Paul Vuillemin
(B) Robert Koch
(C) Félix-Archimède Pouchet
(D) Robin Warren
Answer: (D) Robin Warren
Explanation: Robin Warren and Barry Marshall demonstrated that Helicobacter pylori plays a major role in gastritis and many peptic ulcers. Their discovery challenged the belief that ulcers resulted mainly from stress or excess acid, opening the way for antibiotic-based treatment.
Q80. Who discovered the cell nucleus?
[SSC Stenographer – 2024]
(A) Robert Hooke
(B) Antonie van Leeuwenhoek
(C) Robert Brown
(D) James Watson
Answer: (C) Robert Brown
Explanation: Robert Brown described the nucleus in plant cells in 1831. This membrane-bound structure contains most of the genetic material in eukaryotic cells. Hooke had earlier named cells, but did not identify the nucleus as a distinct cellular component.
Q79. Who used microscopes of his own making to observe microorganisms and is often called the father of microbiology?
[SSC Stenographer – 2024]
(A) Matthias Schleiden
(B) Robert Brown
(C) Antonie van Leeuwenhoek
(D) Rudolf Virchow
Answer: (C) Antonie van Leeuwenhoek
Explanation: Antonie van Leeuwenhoek crafted powerful single-lens microscopes and observed bacteria and protozoa in the seventeenth century. He documented these microscopic organisms in letters to the Royal Society, revealing a previously unseen biological world.
Q78. Who arranged the then-known elements so that the properties of every eighth element repeated, proposing the law of octaves?
[SSC Stenographer – 2024]
(A) Johannes van Spronsen
(B) Dmitri Mendeleev
(C) John Newlands
(D) Julius Lothar Meyer
Answer: (C) John Newlands
Explanation: John Newlands proposed the law of octaves in 1865 by arranging elements in increasing atomic mass and noticing periodic repetition after seven intervening elements. The idea worked best for lighter elements and preceded Mendeleev’s more successful periodic arrangement.
Q77. Who reconciled Dalton’s atomic ideas with Gay-Lussac’s law of combining gas volumes by proposing a molecular hypothesis in 1811?
[SSC CGL – 2024]
(A) Robert Boyle
(B) Amedeo Avogadro
(C) Fred Hoyle
(D) Jacques Charles
Answer: (B) Amedeo Avogadro
Explanation: Amedeo Avogadro proposed that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. His hypothesis helped distinguish atoms from molecules and explained regular volume relationships observed in gas reactions.
Q76. Which astronomer is associated with observational evidence that the universe is expanding?
[SSC Stenographer – 2024]
(A) Edwin Hubble
(B) Galileo Galilei
(C) C. V. Raman
(D) James Clerk Maxwell
Answer: (A) Edwin Hubble
Explanation: Edwin Hubble established a relationship between galaxies’ recession velocities and their distances in 1929, strongly supporting cosmic expansion. Earlier theoretical work by Georges Lemaître was also pivotal. This observation became a foundation of modern cosmology.
Q75. Who proposed that every chemical element consists of a distinct kind of atom having its own characteristic mass?
[SSC CGL – 2023]
(A) Antoine Lavoisier
(B) John Dalton
(C) Amedeo Avogadro
(D) Robert Boyle
Answer: (B) John Dalton
Explanation: John Dalton developed his atomic theory in the early nineteenth century. He proposed that each element contains its own kind of atom, distinct in mass and chemical behaviour from those of other elements. Modern science later refined several aspects of this theory.
Q74. Who showed that diborane could reduce aldehydes and ketones via organoboron intermediates to yield alcohols after hydrolysis?
[SSC CGL – 2023]
(A) H. C. Brown
(B) Hugo Rudolph Kruyt
(C) Arthur Stoll
(D) Arne Tiselius
Answer: (A) H. C. Brown
Explanation: Herbert C. Brown advanced boron chemistry and developed useful hydroboration and reduction reactions. His organoborane methods expanded ways to transform organic molecules selectively. Brown shared the 1979 Nobel Prize in Chemistry for work involving organoboron compounds.
Q73. Whose experimental work contributed significantly to the understanding of surface tension and behaviour at liquid interfaces?
[SSC CGL – 2023]
(A) Gerty Cori
(B) Nettie Stevens
(C) Lise Meitner
(D) Agnes Pockels
Answer: (D) Agnes Pockels
Explanation: Agnes Pockels studied surface films and surface tension using experiments devised at home. Her measurements helped establish early surface chemistry, despite her lack of formal university access. Her findings influenced later investigations of monolayers and interfacial phenomena.
Q72. In which year did Tim Berners-Lee invent the World Wide Web, as specified in the examination question?
[SSC CHSL (2022 cycle) – 2023]
(A) 1982
(B) 1995
(C) 1990
(D) 1985
Answer: (C) 1990
Explanation: Tim Berners-Lee proposed the World Wide Web at CERN in 1989 and developed its first working components around 1990. He created foundations including HTML, URLs and HTTP, allowing documents to be linked and accessed across the Internet.
Q71. Who is commonly known as the father of the hydrogen bomb?
[SSC CHSL (memory-based) – 2023]
(A) Wernher von Braun
(B) Edward Teller
(C) Samuel Cohen
(D) None of these
Answer: (B) Edward Teller
Explanation: Edward Teller is widely associated with the development of thermonuclear weapons, particularly work on the Teller–Ulam design alongside Stanislaw Ulam. The label describes his prominent historical role, rather than sole invention by one scientist.
Q70. Who discovered four of Jupiter’s largest moons through telescopic observations in early 1610?
[SSC CGL – 2022]
(A) Simon Marius
(B) Tycho Brahe
(C) Galileo Galilei
(D) Johannes Kepler
Answer: (C) Galileo Galilei
Explanation: Galileo observed four large moons orbiting Jupiter in January 1610. These Galilean moons—Io, Europa, Ganymede and Callisto—provided evidence that not every celestial object revolves around Earth, strengthening challenges to traditional geocentric astronomy.
Q69. Who developed the modern periodic classification of elements on the basis of atomic number?
[RRB Group D – 2022]
(A) Johann Döbereiner
(B) Dmitri Mendeleev
(C) John Newlands
(D) Henry Moseley
Answer: (D) Henry Moseley
Explanation: Henry Moseley showed in 1913 that atomic number, not atomic mass, provides the correct fundamental order for chemical elements. His X-ray measurements resolved several periodic-table anomalies and underpin the modern periodic law.
Q68. Who invented an early electric battery capable of providing a steady current in 1800?
[SSC CHSL – 2022]
(A) Alessandro Volta
(B) Michael Faraday
(C) Luigi Galvani
(D) Henri Becquerel
Answer: (A) Alessandro Volta
Explanation: Alessandro Volta assembled alternating metal discs separated by brine-soaked material to build the voltaic pile around 1800. This invention supplied a relatively continuous electric current and accelerated experiments in electrochemistry and the study of electricity.
Q67. Who discovered penicillin?
[RRB NTPC – 2021]
(A) Charles Darwin
(B) Alexander Fleming
(C) Gregor Mendel
(D) Louis Pasteur
Answer: (B) Alexander Fleming
Explanation: Fleming found that Penicillium mould prevented nearby bacteria from growing in 1928. Penicillin subsequently became a landmark antibiotic, saving many lives after research teams developed purification, production and clinical applications during the 1940s.
Q66. Who invented the mercury-in-glass thermometer and developed a widely used temperature scale?
[RRB NTPC – 2021]
(A) Anders Celsius
(B) Galileo Galilei
(C) Grand Duke of Tuscany
(D) Daniel Gabriel Fahrenheit
Answer: (D) Daniel Gabriel Fahrenheit
Explanation: Daniel Gabriel Fahrenheit improved mercury thermometers in the early eighteenth century and introduced the Fahrenheit temperature scale. Mercury’s relatively uniform expansion helped make temperature readings reproducible, supporting advances in laboratory science and meteorological measurements.
Q65. Who discovered the major human blood groups?
[RRB NTPC – 2021]
(A) Isaac Newton
(B) Karl Landsteiner
(C) Dmitri Mendeleev
(D) Alexander Fleming
Answer: (B) Karl Landsteiner
Explanation: Karl Landsteiner identified the ABO blood-group system in 1900–1901. His discovery helped explain dangerous reactions during incompatible transfusions and made systematic blood matching possible, transforming the safety of transfusion medicine.
Q64. Who is traditionally credited with inventing paper in ancient China?
[RRB NTPC – 2021]
(A) Baudhayan
(B) Cai Lun
(C) Mahaviracharya
(D) Varahamihira
Answer: (B) Cai Lun
Explanation: Cai Lun is traditionally credited with improving and standardizing papermaking around 105 CE during the Han dynasty. Earlier paper-like materials existed, but the process associated with him helped make inexpensive writing surfaces widely available.
Q63. Who discovered the atomic nucleus?
[RRB NTPC – 2021]
(A) Ernest Rutherford
(B) J. J. Thomson
(C) James Chadwick
(D) Niels Bohr
Answer: (A) Ernest Rutherford
Explanation: Rutherford interpreted the results of the gold-foil scattering experiment in 1911 as evidence of a small, dense, positively charged atomic centre. This nuclear model replaced the earlier plum-pudding concept and opened a new era in atomic physics.
Q62. Who is considered the father of nuclear physics?
[RRB NTPC (2019 recruitment) – 2021]
(A) Niels Bohr
(B) James Chadwick
(C) Ernest Rutherford
(D) J. J. Thomson
Answer: (C) Ernest Rutherford
Explanation: Ernest Rutherford’s research transformed understanding of radioactivity, atomic structure and nuclear transformations. He distinguished types of radiation and developed the nuclear model of the atom. These foundational achievements earned him the widely used title father of nuclear physics.
Q61. What did Douglas Engelbart invent?
[RRB NTPC (2019 recruitment) – 2021]
(A) Compact disc
(B) USB port
(C) Floppy disk
(D) Computer mouse
Answer: (D) Computer mouse
Explanation: Douglas Engelbart demonstrated an early computer mouse in the 1960s as part of research into interactive computing. The pointing device helped people control on-screen interfaces, contributing to later graphical user interfaces and personal-computer interaction.
Q60. Who discovered X-rays?
[RRB NTPC (2019 recruitment) – 2021]
(A) Isaac Newton
(B) Wilhelm Röntgen
(C) Henri Becquerel
(D) Guglielmo Marconi
Answer: (B) Wilhelm Röntgen
Explanation: Wilhelm Conrad Röntgen identified X-rays in 1895 while experimenting with cathode-ray tubes. Their ability to pass through soft tissue more easily than bone quickly led to medical imaging. He received the first Nobel Prize in Physics in 1901.
Q59. Which Nobel laureate discovered the role of mosquitoes in transmitting malaria?
[RRB NTPC (2019 recruitment) – 2021]
(A) Robert G. Edwards
(B) Ronald Ross
(C) Paul Lauterbur
(D) Karl Landsteiner
Answer: (B) Ronald Ross
Explanation: Ronald Ross showed in the 1890s that mosquitoes transmit malaria parasites, an essential breakthrough for understanding and controlling the disease. He received the 1902 Nobel Prize in Physiology or Medicine for his research on malaria transmission.
Q58. Who is associated with making the earliest compound microscope?
[SSC MTS (2020 cycle) – 2021]
(A) William Gilbert
(B) Zacharias Janssen
(C) John Harington
(D) Galileo Galilei
Answer: (B) Zacharias Janssen
Explanation: Zacharias Janssen and his father Hans are traditionally associated with early compound microscopes in the late sixteenth century. Combining objective and eyepiece lenses increases magnification, making it possible to examine tiny objects beyond normal eyesight.
Q57. Who invented the agricultural seed drill?
[RPSC Assistant Professor (History) – 2021]
(A) Jethro Tull
(B) Lord Townshend
(C) Richard Roberts
(D) Cotton gin
Answer: (A) Jethro Tull
Explanation: Jethro Tull developed an improved mechanical seed drill around 1701. It placed seeds at more regular depths and intervals than broadcasting by hand, helping make crop establishment more efficient during agricultural changes in eighteenth-century Britain.
Q56. Who invented the water frame for spinning yarn?
[RPSC Assistant Professor (History) – 2021]
(A) Edmund Cartwright
(B) Whitley
(C) John Kay
(D) Richard Arkwright
Answer: (D) Richard Arkwright
Explanation: Richard Arkwright patented the water frame in 1769. Powered spinning machinery produced stronger cotton yarn and helped expand the factory system. Unlike a weaving loom, this invention transformed the spinning stage of textile manufacture.
Q55. Who discovered natural radioactivity?
[WBCS Prelims – 2020]
(A) Marie Curie
(B) Ernest Rutherford
(C) Henri Becquerel
(D) Enrico Fermi
Answer: (C) Henri Becquerel
Explanation: Henri Becquerel found in 1896 that uranium compounds spontaneously emitted penetrating radiation without exposure to sunlight. His discovery launched the study of radioactivity, later advanced by Marie and Pierre Curie and Ernest Rutherford.
Q54. Who discovered and named the cell?
[RRB NTPC – 2020]
(A) Theodor Schwann
(B) Matthias Schleiden
(C) Robert Hooke
(D) Rudolf Virchow
Answer: (C) Robert Hooke
Explanation: Robert Hooke introduced the term cell after viewing cork under a microscope and publishing his observations in Micrographia in 1665. He saw empty, box-like structures that were actually the walls of dead plant cells.
Q53. Which of the following was invented by Walter Hunt?
[SSC CHSL – 2020]
(A) Ship
(B) Scooter
(C) Safety lamp
(D) Safety pin
Answer: (D) Safety pin
Explanation: Walter Hunt patented the modern safety pin in 1849. Its spring and protective clasp help keep the sharp point enclosed. The invention illustrates how a small mechanical improvement can make an everyday fastening tool considerably safer.
Q52. What did Wilhelm Conrad Röntgen discover?
[SSC CHSL – 2020]
(A) Conservation of electric charge
(B) Electric bulb
(C) X-rays
(D) Thermodynamics
Answer: (C) X-rays
Explanation: Röntgen discovered X-rays in 1895 while observing fluorescence near a cathode-ray apparatus. Because the rays penetrate some materials more than others, they enabled pictures of bones and other internal structures, revolutionizing diagnostic medicine.
Q51. Who invented the first successful powered aeroplane?
[SSC CHSL – 2020]
(A) Orville and Wilbur Wright
(B) Auguste and Louis Lumière
(C) Alexander Graham Bell
(D) Louis Pasteur and Alexander Fleming
Answer: (A) Orville and Wilbur Wright
Explanation: Orville and Wilbur Wright achieved controlled, sustained powered flight in December 1903 at Kitty Hawk. Their work combined a powered aircraft with effective three-axis control, a decisive step toward practical aviation.
Q50. Who among the following scientists invented dynamite?
[SSC CHSL – 2020]
(A) Alfred Nobel
(B) Thomas Alva Edison
(C) Rudolf Diesel
(D) Benjamin Franklin
Answer: (A) Alfred Nobel
Explanation: Alfred Nobel patented dynamite in 1867 by stabilizing nitroglycerin in an absorbent material. It made blasting more manageable for construction and mining. Nobel later established prizes that reward outstanding contributions in several disciplines.
Q49. Which chemical element was discovered by William Crookes?
[SSC CGL – 2019]
(A) Germanium
(B) Beryllium
(C) Plutonium
(D) Thallium
Answer: (D) Thallium
Explanation: William Crookes discovered thallium in 1861 using spectroscopy, detecting a distinctive green spectral line. The element’s name derives from a Greek word meaning green shoot. Spectral analysis became a powerful tool for identifying previously unknown elements.
Q48. Who pioneered vaccination by developing the first successful smallpox vaccine?
[SSC CGL – 2019]
(A) John Hunter
(B) Alexander Fleming
(C) Louis Pasteur
(D) Edward Jenner
Answer: (D) Edward Jenner
Explanation: Edward Jenner demonstrated in 1796 that exposure to cowpox could protect against smallpox. This experiment began the development of vaccination as a preventive medical practice, eventually contributing to the global eradication of smallpox.
Q47. Who discovered and scientifically explained microbial fermentation?
[RPF Constable – 2019]
(A) Alexander Fleming
(B) Robert Koch
(C) Edward Jenner
(D) Louis Pasteur
Answer: (D) Louis Pasteur
Explanation: Louis Pasteur showed that fermentation is a biological process carried out by microorganisms rather than a purely chemical transformation. His investigations helped establish germ theory and led to important developments in food preservation and microbiology.
Q46. Who invented the World Wide Web in 1989?
[SSC CHSL – 2019]
(A) Charles Babbage
(B) Steve Wozniak
(C) Tim Berners-Lee
(D) Bill Gates
Answer: (C) Tim Berners-Lee
Explanation: Tim Berners-Lee proposed a hypertext-based information system at CERN in 1989. It developed into the World Wide Web, linking documents through web addresses. The Web uses the Internet but is not synonymous with the entire Internet.
Q45. Who is associated with the invention and development of alternating-current power systems?
[RRB Group D – 2018]
(A) Isaac Newton
(B) Thomas Edison
(C) Nikola Tesla
(D) Albert Einstein
Answer: (C) Nikola Tesla
Explanation: Nikola Tesla made major contributions to practical polyphase alternating-current generation and motors. Alternating current itself emerged through work by multiple inventors; Tesla’s systems were especially important for economical long-distance electrical transmission.
Q44. Who developed a theory of nuclear forces based on exchange particles?
[RRB Group D – 2018]
(A) Satyendra Nath Bose
(B) Hideki Yukawa
(C) Jagadish Chandra Bose
(D) J. J. Thomson
Answer: (B) Hideki Yukawa
Explanation: Hideki Yukawa proposed that the strong nuclear force between nucleons could be explained through exchange of a massive particle later called a meson. His theoretical work earned the 1949 Nobel Prize in Physics.
Q43. Which ancient Greek thinker used the term atomos for an indivisible particle?
[RRB Group D – 2018]
(A) John Dalton
(B) Kanada
(C) Antoine Lavoisier
(D) Democritus
Answer: (D) Democritus
Explanation: Democritus proposed that matter is composed of tiny indivisible units called atomos. His idea was philosophical rather than experimental. Scientific atomic theory emerged much later through measurements and work by chemists such as John Dalton.
Q42. Who is most closely associated with the periodic table of chemical elements?
[RRB Group D – 2018]
(A) John Newlands
(B) Friedrich Hund
(C) Dmitri Mendeleev
(D) Alfred Nobel
Answer: (C) Dmitri Mendeleev
Explanation: Dmitri Mendeleev published an influential periodic table in 1869 based largely on recurring properties and atomic masses. He left gaps for undiscovered elements and predicted their characteristics, an important reason his classification was widely adopted.
Q41. Who invented the smart glove known as TJay, designed to help predict epileptic seizures?
[RRB Group D – 2018]
(A) Rajlakshmi Borthakur
(B) Ankita Deka
(C) Archana S. R.
(D) Chayanika Baruah
Answer: (A) Rajlakshmi Borthakur
Explanation: Rajlakshmi Borthakur developed the TJay smart glove concept to monitor physiological signals linked with seizures. Such wearable inventions show how sensors and computing can be integrated to provide early alerts, though performance depends on careful clinical validation.
Q40. Which of the following is associated with Wilhelm Röntgen?
[UPPSC Civil Services – 2018]
(A) Radio
(B) X-ray machine
(C) Electric bulb
(D) None of these
Answer: (B) X-ray machine
Explanation: Wilhelm Röntgen discovered X-rays in 1895; this discovery made X-ray imaging instruments possible. X-rays are high-energy electromagnetic radiation capable of penetrating many materials, enabling non-invasive views of bones and other internal structures.
Q39. Which scientist–invention pair is NOT correctly matched?
[UPPSC LT Grade Science – 2018]
(A) Computer — Charles Babbage
(B) Radio — Karl Benz
(C) Barometer — Evangelista Torricelli
(D) Dynamo — Michael Faraday
Answer: (B) Radio — Karl Benz
Explanation: Karl Benz pioneered the gasoline-powered automobile, not radio. Wireless radio communication is especially associated with Guglielmo Marconi. Babbage, Torricelli and Faraday are respectively linked with early computing concepts, the mercury barometer and electromagnetic induction.
Q38. What was invented by J. B. Dunlop?
[SSC CGL – 2017]
(A) Aeroplane
(B) Motor car
(C) Pneumatic rubber tyre
(D) Rubber boot
Answer: (C) Pneumatic rubber tyre
Explanation: John Boyd Dunlop developed a practical pneumatic tyre in 1887–1888 for a bicycle. Air-filled tyres improved comfort and reduced vibration compared with solid rubber versions. Pneumatic tyre technology was later adapted extensively for motor vehicles.
Q37. Who investigated electricity, invented the lightning rod and helped develop bifocal spectacles?
[SSC CGL – 2017]
(A) Kirkpatrick Macmillan
(B) Benjamin Franklin
(C) William Henry Fox Talbot
(D) Alexander Fleming
Answer: (B) Benjamin Franklin
Explanation: Benjamin Franklin’s electrical experiments linked lightning with electricity and inspired his lightning-rod design. He also developed bifocal spectacles. Electricity was known before Franklin, so his achievement was research and invention rather than discovering electricity itself.
Q36. Who is credited with developing Bluetooth wireless technology?
[SSC CGL – 2017]
(A) Kirkpatrick Macmillan
(B) Benjamin Franklin
(C) Jaap Haartsen
(D) Charles Babbage
Answer: (C) Jaap Haartsen
Explanation: Jaap Haartsen played a leading role in developing Bluetooth technology at Ericsson in the 1990s. It enables short-range wireless communication using radio frequencies, allowing devices such as headphones, keyboards and smartphones to exchange information.
Q35. Who invented an early electric tram?
[SSC CGL – 2017]
(A) James Cook
(B) William Harvey
(C) Fyodor Pirotsky
(D) Robert Boyle
Answer: (C) Fyodor Pirotsky
Explanation: Fyodor Pirotsky, a Russian engineer, experimented with electricity-powered railway cars during the nineteenth century. His work helped demonstrate electric traction, which later reshaped urban public transport through electric trams and railways.
Q34. Who is popularly associated with the development of the Pentium processor?
[SSC CGL – 2017]
(A) C. Kumar N. Patel
(B) Tom Gunter
(C) Vince Emery
(D) Vinod Dham
Answer: (D) Vinod Dham
Explanation: Vinod Dham was a key engineer and leader involved in Intel’s Pentium microprocessor development. He is sometimes nicknamed the father of the Pentium chip, although processors result from collaborative engineering involving large teams.
Q33. Who developed an early waterproof raincoat using rubberized fabric?
[SSC CGL – 2017]
(A) Robert Hooke
(B) Cai Lun
(C) Charles Macintosh
(D) William Harvey
Answer: (C) Charles Macintosh
Explanation: Charles Macintosh patented a waterproof fabric in 1823 by bonding textile layers using dissolved rubber. Coats made from this material became known as mackintoshes. The invention helped popularize rainwear capable of resisting water penetration.
Q32. Who invented the hot-air balloon?
[SSC CGL – 2017]
(A) Montgolfier brothers
(B) Wright brothers
(C) Lisitsyn brothers
(D) Walton brothers
Answer: (A) Montgolfier brothers
Explanation: Joseph-Michel and Jacques-Étienne Montgolfier developed hot-air balloons in eighteenth-century France. Their public demonstrations in 1783 led to some of the first successful human flights, using heated air to provide buoyant lift.
Q31. Who invented dynamite?
[SSC CGL – 2017]
(A) John Boyd Dunlop
(B) Alfred Nobel
(C) James Simons
(D) Peter Hargreaves
Answer: (B) Alfred Nobel
Explanation: Alfred Nobel developed dynamite by combining nitroglycerin with an absorbent material, making an explosive easier to handle. Patented in 1867, it was used for mining and infrastructure projects, though its military implications were also significant.
Q30. Who invented the Space Pen?
[SSC CGL – 2017]
(A) Paul C. Fisher
(B) Rudolf Diesel
(C) Wright brothers
(D) Alexander Fleming
Answer: (A) Paul C. Fisher
Explanation: Paul C. Fisher developed a pressurized ink cartridge that could write in unusual orientations and low-gravity conditions. Fisher Space Pens were adopted for space missions. The pen does not depend on gravity alone to feed ink toward its tip.
Q29. Who invented the electrocardiogram (ECG) instrument?
[SSC CGL – 2017]
(A) Willem Einthoven
(B) Edward Jenner
(C) Antonio de Ulloa and Charles Wood
(D) Karl Benz
Answer: (A) Willem Einthoven
Explanation: Willem Einthoven developed the string galvanometer and advanced electrocardiography around the beginning of the twentieth century. An ECG records electrical activity associated with the heartbeat and is widely used to assess heart rhythm and other cardiac conditions.
Q28. Who invented an early practical television system?
[SSC CGL – 2017]
(A) Michael Faraday
(B) Joseph Henry
(C) Abbé Caselli
(D) John Logie Baird
Answer: (D) John Logie Baird
Explanation: John Logie Baird demonstrated an early mechanical television system in the 1920s. His apparatus transmitted moving visual images, preceding the widespread adoption of fully electronic television, which developed through contributions by several other inventors.
Q27. Who invented the hook-and-loop fastener known as Velcro?
[SSC CGL – 2017]
(A) Thomas Edison
(B) William Harvey
(C) George de Mestral
(D) Robert Boyle
Answer: (C) George de Mestral
Explanation: Swiss engineer George de Mestral conceived hook-and-loop fastening after observing how burdock burrs attached to clothing and animal fur. The resulting Velcro system uses tiny hooks and loops to make a reusable fastener.
Q26. Who discovered the proton?
[SSC CGL – 2017]
(A) Ernest Rutherford
(B) Friedrich Miescher
(C) Henri Becquerel
(D) Henry Cavendish
Answer: (A) Ernest Rutherford
Explanation: Rutherford identified the hydrogen nucleus as a fundamental positively charged particle through nuclear-reaction experiments reported around 1917–1919. This particle came to be called the proton and forms part of every ordinary atomic nucleus.
Q25. Who discovered the planet Uranus?
[SSC CGL – 2017]
(A) Isaac Newton
(B) William Henry Fox Talbot
(C) William Herschel
(D) Nicolaus Copernicus
Answer: (C) William Herschel
Explanation: William Herschel observed Uranus in 1781 and initially thought it might be a comet. Follow-up observations revealed its planetary orbit, making it the first planet discovered in modern times with the help of a telescope.
Q24. Who is credited with describing the circulation of blood through the human body?
[SSC CGL – 2017]
(A) Thomas Edison
(B) William Harvey
(C) Robert Hooke
(D) Robert Boyle
Answer: (B) William Harvey
Explanation: William Harvey published a systematic explanation of blood circulation in 1628. He argued that the heart pumps blood around the body continuously, overturning longstanding theories and establishing an important basis for cardiovascular physiology.
Q23. Who introduced the idea of light quanta, later called photons?
[SSC CGL – 2017]
(A) George Crum
(B) Albert Einstein
(C) Henry Cavendish
(D) Humphry Davy
Answer: (B) Albert Einstein
Explanation: Albert Einstein proposed in 1905 that light exchanges energy in discrete packets, explaining features of the photoelectric effect. These light quanta became known as photons. The idea contributed decisively to the development of quantum physics.
Q22. Who is associated with the discovery of insulin?
[SSC CGL – 2017]
(A) Alexander Fleming
(B) Frederick Banting
(C) James Watt
(D) F. G. Hopkins
Answer: (B) Frederick Banting
Explanation: Frederick Banting and Charles Best played central roles in isolating insulin in 1921, working with J. J. R. Macleod and James Collip. Insulin transformed diabetes management by making it possible to treat deficient insulin production.
Q21. Who invented a commercially important form of stainless steel?
[RRB NTPC – 2016]
(A) William Howard Livens
(B) Joseph Aspdin
(C) Harry Brearley
(D) James Dyson
Answer: (C) Harry Brearley
Explanation: Harry Brearley developed an early stainless steel alloy in 1913 while researching corrosion-resistant steel. Chromium forms a protective oxide layer, helping the metal resist rust. Stainless steel later became essential in manufacturing, medicine and household products.
Q20. Who discovered the principle of buoyancy?
[RRB NTPC – 2016]
(A) Archimedes
(B) Blaise Pascal
(C) Isaac Newton
(D) Galileo Galilei
Answer: (A) Archimedes
Explanation: Archimedes’ principle states that a body in a fluid experiences an upward buoyant force equal to the weight of the displaced fluid. This idea explains floating ships, submerged objects and the operation of hydrometers.
Q19. Who is credited in this examination with the discovery of carbon nanotubes?
[RPSC Assistant Engineer – 2016]
(A) Arthur Compton
(B) Abdus Salam
(C) Sumio Iijima
(D) Kip Thorne
Answer: (C) Sumio Iijima
Explanation: Sumio Iijima reported detailed observations of multiwalled carbon nanotubes in 1991, helping launch intensive research on these cylindrical carbon structures. Their mechanical strength, electrical characteristics and high aspect ratios support research into advanced materials and devices.
Q18. Alexander Fleming discovered which of the following?
[MPPSC State Services – 2016]
(A) Penicillin
(B) X-rays
(C) Streptomycin
(D) Telephone
Answer: (A) Penicillin
Explanation: Alexander Fleming discovered the antibacterial effect of penicillin in 1928. X-rays were discovered by Wilhelm Röntgen; streptomycin emerged from research by Albert Schatz and colleagues; the telephone is associated with Alexander Graham Bell.
Q17. Who discovered the antibiotic-producing fungus of the genus Penicillium?
[UPSC NDA – 2015]
(A) Louis Pasteur
(B) Sir Alexander Fleming
(C) Stanley Prusiner
(D) Robert Hooke
Answer: (B) Sir Alexander Fleming
Explanation: Fleming observed a Penicillium mould producing a substance that inhibited bacteria. He named the substance penicillin, which subsequently became a clinically important antibiotic following further research and manufacturing advances by other scientists.
Q16. Alexander Fleming discovered which of the following?
[MPPSC State Services – 2015]
(A) Penicillin
(B) X-rays
(C) Streptomycin
(D) Telephone
Answer: (A) Penicillin
Explanation: Penicillin was discovered by Alexander Fleming in 1928 during bacterial-culture experiments. Röntgen discovered X-rays, while Alexander Graham Bell is linked with the telephone. Streptomycin was discovered later by a research group involving Albert Schatz.
Q15. Who showed through scientific experiments that plants respond to stimuli and display life processes?
[MPPSC State Services – 2015]
(A) Robert Koch
(B) Jagadish Chandra Bose
(C) Benjamin Franklin
(D) Louis Pasteur
Answer: (B) Jagadish Chandra Bose
Explanation: Jagadish Chandra Bose conducted pioneering experiments on electrical and mechanical responses in plants. His crescograph magnified tiny growth movements, demonstrating that plant responses could be measured precisely, even though plant life was already known long before his work.
Q14. Who invented the xerographic process?
[RPSC College Librarian – 2014]
(A) Chester Carlson
(B) Benjamin Dancer
(C) Charles Babbage
(D) Paul Otlet
Answer: (A) Chester Carlson
Explanation: Chester Carlson invented electrophotography, later called xerography, in 1938. The technique uses electrostatic charges and light-sensitive materials to create images with toner. It became the basis of modern office photocopying and many laser printers.
Q13. Consider these scientist–theory pairs:
1. Continental drift — Edwin Hubble;
2. Expansion of the universe — Alfred Wegener;
3. Photoelectric effect — Albert Einstein.
Which pair is correctly matched?
[UPSC CSE Prelims – 2008]
(A) 2 and 3 only
(B) 3 only
(C) 2 only
(D) 1 only
Answer: (B) 3 only
Explanation: Alfred Wegener proposed continental drift, whereas Edwin Hubble contributed observations supporting an expanding universe; the first two pairings are reversed. Albert Einstein explained the photoelectric effect using light quanta, so only the third pair is correctly matched.
Q12. Which scientist shared a Nobel Prize in Physics with his son?
[UPSC CSE Prelims – 2008]
(A) Max Planck
(B) Albert Einstein
(C) William Henry Bragg
(D) Enrico Fermi
Answer: (C) William Henry Bragg
Explanation: William Henry Bragg and his son William Lawrence Bragg jointly received the 1915 Nobel Prize in Physics for their analysis of crystal structures using X-rays. Their work established X-ray crystallography as an important scientific method.
Q11. Which set of associations is correctly matched:
1. Francis Collins — human genome mapping;
2. Sergey Brin — Google;
3. Jimmy Wales — Wikipedia?
[UPSC CSE Prelims – 2008]
(A) 1 and 2 only
(B) 2 and 3 only
(C) 3 only
(D) 1, 2 and 3
Answer: (D) 1, 2 and 3
Explanation: Francis Collins directed the public Human Genome Project during a major phase of its work. Sergey Brin co-founded Google with Larry Page, and Jimmy Wales co-founded Wikipedia. All three associations are correctly matched.
Q10. The Nobel Prize–winning scientist James D. Watson is particularly known for work in which field?
[UPSC CSE Prelims – 2008]
(A) Metallurgy
(B) Meteorology
(C) Environmental protection
(D) Genetics
Answer: (D) Genetics
Explanation: James Watson is best known for research on DNA structure, especially the double-helix model presented with Francis Crick in 1953. This work was foundational for molecular genetics and understanding how hereditary information is stored.
Q9. The 2006 Nobel Prize in Physiology or Medicine was awarded for research broadly relating to which field?
[UPSC CSE Prelims – 2007]
(A) Prevention of weakening due to ageing
(B) Flow of genetic information
(C) Immunology and disease resistance
(D) Adult stem-cell research
Answer: (B) Flow of genetic information
Explanation: Andrew Fire and Craig Mello received the 2006 medicine Nobel for discovering RNA interference, a mechanism by which double-stranded RNA can silence particular genes. This regulates the flow of genetic information into functional products.
Q8. Match A. John C. Mather, B. Michael Griffin, C. Paul G. Allen and D. Piers Sellers with
1. Microsoft co-founder, 2. Spacewalker, 3. NASA administrator, 4. 2006 Physics Nobel laureate.
[UPSC CSE Prelims – 2007]
(A) A-4, B-1, C-3, D-2
(B) A-2, B-3, C-1, D-4
(C) A-4, B-3, C-1, D-2
(D) A-2, B-1, C-3, D-4
Answer: (C) A-4, B-3, C-1, D-2
Explanation: John Mather shared the 2006 Physics Nobel for cosmic-background research. Michael Griffin led NASA; Paul Allen co-founded Microsoft; astronaut Piers Sellers performed spacewalks. Thus the correct sequence of associations is 4, 3, 1, 2.
Q7. Which person–achievement pair is NOT correctly matched?
[UPSC CSE Prelims – 2007]
(A) William Dickson — Motion picture film
(B) Charles Babbage — Programmable computer
(C) Nicholas Stern — Construction technology
(D) Brian Greene — String theory
Answer: (C) Nicholas Stern — Construction technology
Explanation: Nicholas Stern is an economist known for work on climate-change economics, notably the Stern Review, not construction technology. Dickson helped develop motion-picture technology, Babbage designed computational machines, and Brian Greene is known for work popularizing string theory.
Q6. Who invented the laser?
[UPSC CSE Prelims – 2005]
(A) Theodore Maiman
(B) Denis Papin
(C) William Morton
(D) Francis Crick
Answer: (A) Theodore Maiman
Explanation: Theodore Maiman built the first working laser in 1960 using a ruby crystal. Lasers produce intense, directional, coherent light through stimulated emission of radiation, an underlying concept developed through earlier theoretical and experimental physics.
Q5. Consider the statements:
1. Adam Osborne produced the first portable computer.
2. Ian Wilmut created the first cloned sheep.
Which is/are correct?
[UPSC CSE Prelims – 2004]
(A) 1 only
(B) 2 only
(C) Both 1 and 2
(D) Neither 1 nor 2
Answer: (C) Both 1 and 2
Explanation: Adam Osborne’s company introduced the Osborne 1, an influential early portable computer, in 1981. Ian Wilmut led the team responsible for cloning Dolly the sheep using an adult somatic cell. Both statements reflect the associations accepted by the examination.
Q4. Which person–field pair is incorrectly matched?
[UPSC CSE Prelims – 2004]
(A) Reinhold Messner — Computer technology
(B) Harlow Shapley — Astronomy
(C) Gregor Mendel — Heredity
(D) Godfrey Hounsfield — CT scan
Answer: (A) Reinhold Messner — Computer technology
Explanation: Reinhold Messner is an accomplished mountaineer, not a computer technologist. Harlow Shapley was an astronomer, Mendel established important principles of heredity, and Godfrey Hounsfield helped develop computed tomography for medical imaging.
Q3. Paul Lauterbur and Peter Mansfield won the 2003 Nobel Prize in Medicine for research concerning which technology?
[UPSC CSE Prelims – 2004]
(A) Control of AIDS
(B) Magnetic resonance imaging
(C) Respiratory diseases
(D) Genetic engineering
Answer: (B) Magnetic resonance imaging
Explanation: Paul Lauterbur and Peter Mansfield developed methods that enabled magnetic resonance imaging, including spatial encoding and rapid image acquisition. MRI uses magnetic fields and radio waves to produce detailed views of internal structures without ionizing X-ray radiation.
Q2. Who is credited in this examination with the invention of the simple microscope?
[WBCS Prelims – 2002]
(A) Robert Hooke
(B) Antonie van Leeuwenhoek
(C) Jan Evangelista Purkinje
(D) Robert Brown
Answer: (B) Antonie van Leeuwenhoek
Explanation: Antonie van Leeuwenhoek made exceptionally powerful single-lens microscopes in the seventeenth century. These simple instruments allowed him to observe microorganisms and blood cells, advancing microscopy and early microbiology.
Q1. Match A. Arber and Smith, B. Feldman, C. Mullis, D. Temin and Baltimore with:
1. Agrobacterium T-DNA transgenic plants, 2. Endonucleases, 3. Reverse transcriptase, 4. Polymerase chain reaction.
[UPSC CSE Prelims – 2002]
(A) A-2, B-1, C-4, D-3
(B) A-1, B-2, C-4, D-3
(C) A-2, B-1, C-3, D-4
(D) A-1, B-2, C-3, D-4
Answer: (A) A-2, B-1, C-4, D-3
Explanation: Arber and Smith contributed to restriction-endonuclease discoveries; Feldman worked with Agrobacterium T-DNA in plants; Kary Mullis devised PCR; Temin and Baltimore discovered reverse transcriptase. The matching sequence is therefore 2, 1, 4, 3.