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.