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.
