Science and Technology General Knowledge (GK) constitutes a dynamic and high-scoring segment of competitive exams like UPSC, SSC, and State PSCs. This section evaluates an aspirant’s awareness of fundamental scientific principles and recent technological advancements, including space exploration, defense systems, biotechnology, and information technology. Key focus areas typically include milestones achieved by organizations like ISRO and DRDO, global space missions, breakthroughs in renewable energy, and emerging technologies such as Artificial Intelligence (AI) and quantum computing. Mastering this subject requires a blend of static scientific concepts and up-to-date current affairs to accurately tackle objective questions.
1. What is the SI unit of electric current?
Correct Answer: b) Ampere
Explanation:
The Ampere is the standard unit of electrical current in the International System of Units (SI).
2. A Light Year is a unit of measurement for:
Correct Answer: c) Distance
Explanation:
A light-year is the distance that light travels in a vacuum in one Julian year (about 9.46 trillion kilometers).
3. Which of the following describes a sound wave in air?
Correct Answer: b) Longitudinal wave
Explanation:
Sound waves in air are longitudinal waves, meaning the particle displacement is parallel to the direction of wave propagation.
4. Newton's First Law of Motion is also known as the Law of:
Correct Answer: a) Inertia
Explanation:
Newton's First Law is the Law of Inertia, stating an object remains at rest or in uniform motion unless acted upon by a net external force.
5. What is the SI unit of power?
Correct Answer: c) Watt
Explanation:
The SI unit of power is the Watt, equivalent to one joule per second.
6. The power of a lens is measured in:
Correct Answer: b) Diopters
Explanation:
The power of a lens is defined as the reciprocal of its focal length in meters and is measured in Diopters.
7. Which instrument is used to measure atmospheric pressure?
Correct Answer: b) Barometer
Explanation:
A barometer is a scientific instrument used to measure atmospheric pressure, crucial for forecasting short-term changes in the weather.
8. What is the approximate speed of light in a vacuum?
Correct Answer: a) 300,000 km/s
Explanation:
The speed of light in a vacuum is exactly 299,792,458 meters per second, which is approximately 300,000 km/s.
9. Optical fibers work on the principle of:
Correct Answer: c) Total Internal Reflection
Explanation:
Optical fibers use total internal reflection to trap light inside the core, allowing it to travel long distances with minimal loss.
10. The formation of a mirage in a desert is primarily due to:
Correct Answer: b) Total Internal Reflection
Explanation:
A mirage is an optical phenomenon created by the total internal reflection of light in layers of air of different temperatures.
11. Which of the following are the primary colors of light?
Correct Answer: b) Red, Green, Blue
Explanation:
The primary colors of light in the additive color system are red, green, and blue (RGB).
12. The formula for calculating force is:
Correct Answer: c) Mass * Acceleration
Explanation:
According to Newton's Second Law of Motion, Force equals mass times acceleration (F = ma).
13. What is the standard value of acceleration due to gravity on Earth?
Correct Answer: b) 9.8 m/s squared
Explanation:
The standard acceleration due to gravity on the surface of the Earth is approximately 9.8 meters per second squared.
14. The primary source of energy in the Sun is:
Correct Answer: b) Nuclear Fusion
Explanation:
The Sun generates energy through nuclear fusion, primarily fusing hydrogen nuclei into helium in its core.
15. Who discovered X-rays?
Correct Answer: b) Wilhelm Roentgen
Explanation:
Wilhelm Roentgen discovered X-rays in 1895, for which he was awarded the first Nobel Prize in Physics.
16. The electron was discovered by:
Correct Answer: b) J.J. Thomson
Explanation:
J.J. Thomson discovered the electron in 1897 through his experiments with cathode ray tubes.
17. Who is credited with the discovery of the proton?
Correct Answer: a) Ernest Rutherford
Explanation:
Ernest Rutherford is credited with the discovery of the proton in 1919, proving that the hydrogen nucleus is present in other nuclei.
18. The neutron was discovered by:
Correct Answer: c) James Chadwick
Explanation:
James Chadwick discovered the neutron, an uncharged subatomic particle, in 1932.
19. Who discovered the phenomenon of natural radioactivity?
Correct Answer: a) Henri Becquerel
Explanation:
Henri Becquerel discovered natural radioactivity in 1896 while investigating uranium salts.
20. The Theory of Relativity (E=mc^2) was proposed by:
Correct Answer: c) Albert Einstein
Explanation:
Albert Einstein proposed the Theory of Relativity, establishing the equivalence of mass and energy through the equation E=mc^2.
21. Which is the most abundant gas in the Earth's atmosphere?
Correct Answer: c) Nitrogen
Explanation:
Nitrogen makes up about 78% of the Earth's atmosphere, making it the most abundant gas.
22. What is the chemical name for 'Laughing Gas'?
Correct Answer: b) Nitrous oxide
Explanation:
Nitrous oxide (N2O) is commonly known as laughing gas due to its euphoric effects upon inhalation.
23. Dry ice is the solid form of which gas?
Correct Answer: c) Carbon Dioxide
Explanation:
Dry ice is solid carbon dioxide (CO2), which sublimates directly into a gas at room temperature.
24. What is the pH value of pure water at room temperature?
Correct Answer: c) 7
Explanation:
Pure water is neutral, possessing a pH value of exactly 7 at 25 degrees Celsius.
25. Which acid is naturally secreted in the human stomach?
Correct Answer: c) Hydrochloric acid
Explanation:
Hydrochloric acid (HCl) is a major component of gastric acid, aiding in the digestion of food.
26. What is the chemical name of Vitamin C?
Correct Answer: b) Ascorbic acid
Explanation:
The chemical name for Vitamin C is Ascorbic acid, an essential nutrient involved in tissue repair.
27. Which non-metal is liquid at standard room temperature?
Correct Answer: c) Bromine
Explanation:
Bromine is the only non-metallic element that is a liquid at standard room temperature.
28. Which metal remains liquid at room temperature?
Correct Answer: b) Mercury
Explanation:
Mercury is the only metallic element that is liquid at standard conditions for temperature and pressure.
29. What is the heaviest naturally occurring element?
Correct Answer: c) Uranium
Explanation:
Uranium is the heaviest naturally occurring element, with an atomic number of 92.
30. Which is the lightest gas in the periodic table?
Correct Answer: d) Hydrogen
Explanation:
Hydrogen is the lightest chemical element and the lightest gas, with an atomic number of 1.
31. Which gas is the primary contributor to global warming?
Correct Answer: a) Carbon Dioxide
Explanation:
While methane is more potent, carbon dioxide is the most significant long-lived greenhouse gas contributing to global warming.
32. The ozone layer protects the Earth from harmful:
Correct Answer: c) Ultraviolet (UV) radiation
Explanation:
The ozone layer absorbs most of the Sun's harmful ultraviolet (UV) radiation, protecting life on Earth.
33. Brass is primarily an alloy of copper and which other metal?
Correct Answer: b) Zinc
Explanation:
Brass is a metallic alloy that is made of copper and zinc.
34. Bronze is an alloy consisting primarily of copper and:
Correct Answer: b) Tin
Explanation:
Bronze is an alloy consisting primarily of copper, usually with tin as the main additive.
35. Pure gold is represented by how many Karats?
Correct Answer: c) 24 Karat
Explanation:
24 Karat gold is 100% pure gold without any other metals mixed into it.
36. What is the chemical formula for common table salt?
Correct Answer: b) NaCl
Explanation:
Common table salt is sodium chloride, which has the chemical formula NaCl.
37. The chemical name for Baking Soda is:
Correct Answer: b) Sodium Bicarbonate
Explanation:
Baking soda is chemically known as sodium bicarbonate (NaHCO3).
38. The chemical name for Washing Soda is:
Correct Answer: a) Sodium Carbonate
Explanation:
Washing soda is a chemical compound with the formula Na2CO3, known as sodium carbonate.
39. Plaster of Paris is made by partially dehydrating which mineral?
Correct Answer: b) Gypsum
Explanation:
Plaster of Paris is calcium sulfate hemihydrate, produced by heating gypsum to about 150 degrees Celsius.
40. Which of the following chemicals is commonly used in tear gas?
Correct Answer: a) Chloropicrin
Explanation:
Tear gas compounds commonly include CS gas, CR gas, CN gas, and chloropicrin.
41. Which organelle is known as the 'powerhouse of the cell'?
Correct Answer: c) Mitochondria
Explanation:
Mitochondria generate most of the chemical energy needed to power the cell's biochemical reactions.
42. Which organelles are known as the 'suicide bags' of the cell?
Correct Answer: b) Lysosomes
Explanation:
Lysosomes contain digestive enzymes. If the cell is damaged, lysosomes may burst and their enzymes digest their own cell.
43. Which blood group is known as the Universal Donor?
Correct Answer: c) O negative
Explanation:
O negative blood cells have no A, B, or Rh antigens, so they can be safely given to people of any blood type.
44. Which blood group is known as the Universal Recipient?
Correct Answer: b) AB positive
Explanation:
People with AB positive blood can receive red blood cells from any other blood type.
45. How many bones are there in a typical adult human body?
Correct Answer: a) 206
Explanation:
A typical adult human skeleton consists of 206 bones, though infants are born with around 270 bones that fuse as they grow.
46. What is the largest organ in the human body?
Correct Answer: c) Skin
Explanation:
The skin is the body's largest organ, acting as a barrier and protecting internal structures.
47. Which is the largest internal gland in the human body?
Correct Answer: c) Liver
Explanation:
The liver is the largest solid internal organ and the largest gland in the human body.
48. Which gland is known as the 'Master Gland' of the human body?
Correct Answer: c) Pituitary gland
Explanation:
The pituitary gland is called the master gland because it controls the functions of many other endocrine glands.
49. The hormone insulin is produced by which organ?
Correct Answer: c) Pancreas
Explanation:
Insulin is produced by the beta cells in the islets of Langerhans within the pancreas.
50. What is the primary carrier of oxygen in the human blood?
Correct Answer: c) Hemoglobin
Explanation:
Hemoglobin is the iron-containing protein in red blood cells that carries oxygen from the lungs to the body's tissues.
51. Night blindness is caused by the deficiency of which vitamin?
Correct Answer: a) Vitamin A
Explanation:
Vitamin A is essential for good vision, and its deficiency can lead to night blindness (nyctalopia).
52. Rickets is a disease caused by the deficiency of:
Correct Answer: d) Vitamin D
Explanation:
A lack of Vitamin D, calcium, or phosphate leads to rickets, a condition that results in weak or soft bones in children.
53. A deficiency of Vitamin B1 (Thiamine) leads to which disease?
Correct Answer: b) Beriberi
Explanation:
Beriberi is a nutritional disorder caused by a deficiency of thiamine (Vitamin B1).
54. Scurvy is caused by a deficiency of:
Correct Answer: c) Vitamin C
Explanation:
Scurvy is a disease resulting from a lack of Vitamin C (ascorbic acid), which is required for the synthesis of collagen.
55. Anemia is primarily caused by a deficiency of:
Correct Answer: b) Iron
Explanation:
Iron deficiency anemia occurs when the body lacks sufficient iron to produce hemoglobin.
56. Who developed the first successful vaccine, which was for smallpox?
Correct Answer: c) Edward Jenner
Explanation:
Edward Jenner developed the smallpox vaccine in 1796, marking the world's first successful vaccine.
57. Penicillin, the first true antibiotic, was discovered by:
Correct Answer: b) Alexander Fleming
Explanation:
Alexander Fleming discovered penicillin in 1928 when he noticed mold killing staphylococcus bacteria in a petri dish.
58. The scientific study of viruses is known as:
Correct Answer: c) Virology
Explanation:
Virology is the branch of science that deals with the study of viruses and viral diseases.
59. The cell wall of a plant cell is primarily made of:
Correct Answer: c) Cellulose
Explanation:
The plant cell wall consists primarily of cellulose, a complex carbohydrate that provides structural support.
60. The process by which plants make their own food is called:
Correct Answer: c) Photosynthesis
Explanation:
Photosynthesis is the process used by plants, algae, and certain bacteria to harness energy from sunlight to synthesize foods.
61. What was the name of the world's first artificial satellite launched into space?
Correct Answer: b) Sputnik 1
Explanation:
Sputnik 1, launched by the Soviet Union on October 4, 1957, was the first artificial Earth satellite.
62. Who was the first human to journey into outer space?
Correct Answer: c) Yuri Gagarin
Explanation:
Soviet cosmonaut Yuri Gagarin became the first human in space when his Vostok spacecraft completed an orbit of the Earth on April 12, 1961.
63. Who was the first person to walk on the Moon?
Correct Answer: c) Neil Armstrong
Explanation:
Neil Armstrong was the first person to walk on the Moon on July 20, 1969, during the Apollo 11 mission.
64. What was the name of India's first satellite?
Correct Answer: c) Aryabhata
Explanation:
Aryabhata was India's first satellite, named after the famous Indian astronomer, and was launched by the Soviet Union in 1975.
65. In which year was the Indian Space Research Organisation (ISRO) founded?
Correct Answer: b) 1969
Explanation:
ISRO was formed on August 15, 1969, superseding the Indian National Committee for Space Research (INCOSPAR).
66. On which date did India's Chandrayaan-3 successfully land on the Moon?
Correct Answer: a) August 23, 2023
Explanation:
Chandrayaan-3's Vikram lander successfully touched down near the lunar south pole on August 23, 2023.
67. Which launch vehicle was used to launch India's Mars Orbiter Mission (Mangalyaan)?
Correct Answer: b) PSLV-C25
Explanation:
The Mars Orbiter Mission was launched using the Polar Satellite Launch Vehicle (PSLV) designated as PSLV-C25 on November 5, 2013.
68. In what year did NASA launch the James Webb Space Telescope?
Correct Answer: c) 2021
Explanation:
The James Webb Space Telescope, the successor to Hubble, was successfully launched on December 25, 2021.
69. Which is the largest planet in our solar system?
Correct Answer: b) Jupiter
Explanation:
Jupiter is the largest planet in the solar system, with a mass more than two and a half times that of all the other planets combined.
70. Which planet is widely known as the 'Red Planet'?
Correct Answer: c) Mars
Explanation:
Mars is often called the 'Red Planet' because the iron oxide prevalent on its surface gives it a reddish appearance.
71. Which is the hottest planet in the solar system?
Correct Answer: b) Venus
Explanation:
Venus is the hottest planet due to a dense atmosphere of carbon dioxide that creates a runaway greenhouse effect.
72. What is the closest star to the Solar System?
Correct Answer: c) Proxima Centauri
Explanation:
Proxima Centauri is a small, low-mass star located 4.2465 light-years away, making it the closest star to the Sun and the Solar System.
73. Where is India's primary spaceport, the Satish Dhawan Space Centre, located?
Correct Answer: c) Sriharikota
Explanation:
The Satish Dhawan Space Centre (SDSC) is located in Sriharikota, Andhra Pradesh, and is ISRO's main satellite launch center.
74. What does GPS stand for?
Correct Answer: a) Global Positioning System
Explanation:
GPS stands for Global Positioning System, a U.S.-owned utility that provides users with positioning, navigation, and timing services.
75. Which system is generally considered the world's first successful supercomputer?
Correct Answer: b) Cray-1
Explanation:
Designed by Seymour Cray and released in 1976, the Cray-1 is generally considered the first commercially successful supercomputer.
76. What was the name of India's first indigenous supercomputer?
Correct Answer: c) PARAM 8000
Explanation:
PARAM 8000, built by the Centre for Development of Advanced Computing (C-DAC) in 1991, was India's first supercomputer.
77. In computing, CPU stands for:
Correct Answer: c) Central Processing Unit
Explanation:
CPU stands for Central Processing Unit, the primary component of a computer that acts as its brain.
78. Which computer component is often referred to as the 'brain' of the computer?
Correct Answer: d) CPU
Explanation:
The Central Processing Unit (CPU) is called the brain of the computer because it interprets and executes most of the commands from the computer's hardware and software.
79. In computer memory, what does RAM stand for?
Correct Answer: b) Random Access Memory
Explanation:
RAM stands for Random Access Memory, a form of volatile computer memory that can be read and changed in any order.
80. Who is considered the 'Father of the Computer'?
Correct Answer: c) Charles Babbage
Explanation:
Charles Babbage is considered the father of the computer for inventing the first mechanical computer, the Analytical Engine, in the early 19th century.
81. Who is credited with inventing the World Wide Web (WWW)?
Correct Answer: b) Tim Berners-Lee
Explanation:
British computer scientist Sir Tim Berners-Lee invented the World Wide Web in 1989 while working at CERN.
82. What does HTTP stand for in website addresses?
Correct Answer: a) HyperText Transfer Protocol
Explanation:
HTTP stands for HyperText Transfer Protocol, the foundation of data communication for the World Wide Web.
83. In digital computing, how many bits make up 1 Byte?
Correct Answer: b) 8 bits
Explanation:
Historically and almost universally, a byte consists of 8 bits of data.
84. Who holds the first patent for the practical telephone?
Correct Answer: c) Alexander Graham Bell
Explanation:
Alexander Graham Bell was awarded the first US patent for the telephone in 1876.
85. Who is officially credited as the inventor of the radio?
Correct Answer: a) Guglielmo Marconi
Explanation:
Guglielmo Marconi is credited as the inventor of radio for his pioneering work on long-distance radio transmission and his development of Marconi's law.
86. Who invented the first working mechanical television system?
Correct Answer: b) John Logie Baird
Explanation:
Scottish engineer John Logie Baird demonstrated the first working mechanical television system in 1926.
87. Who is widely recognized as the first computer programmer?
Correct Answer: c) Ada Lovelace
Explanation:
Ada Lovelace is considered the first computer programmer for writing an algorithm intended to be carried out by Charles Babbage's early mechanical general-purpose computer, the Analytical Engine.
88. Who coined the term 'Artificial Intelligence' in 1956?
Correct Answer: b) John McCarthy
Explanation:
John McCarthy, an American computer scientist, coined the term 'Artificial Intelligence' for the Dartmouth conference in 1956.
89. What is the underlying technology behind cryptocurrencies like Bitcoin?
Correct Answer: c) Blockchain
Explanation:
Blockchain is the distributed ledger technology that securely records and maintains cryptocurrency transactions across a network of computers.
90. In cellular network technology, what does the 'G' in 5G stand for?
Correct Answer: b) Generation
Explanation:
In 5G, the 'G' stands for Generation, indicating it is the fifth generation of global wireless networking technology.
91. What is the approximate speed of sound in dry air at 20 degrees Celsius?
Correct Answer: a) 343 m/s
Explanation:
The speed of sound in dry air at 20 degrees Celsius (68 degrees Fahrenheit) is approximately 343 meters per second.
92. Which component of blood is primarily responsible for fighting infections?
Correct Answer: c) White Blood Cells
Explanation:
White blood cells (leukocytes) are a part of the immune system and help the body fight infectious disease and foreign invaders.
93. The scientific study of the origin, evolution, and eventual fate of the universe is called:
Correct Answer: b) Cosmology
Explanation:
Cosmology is a branch of astronomy that involves the study of the origin, evolution, and fate of the universe.
94. What fundamental force keeps planets in orbit around the Sun?
Correct Answer: c) Gravity
Explanation:
Gravity is the attractive force that keeps planets in their orbits around the Sun, preventing them from flying off into deep space.
95. An instrument used to detect and record earthquakes is called a:
Correct Answer: a) Seismograph
Explanation:
A seismograph, or seismometer, is an instrument that detects and records the motion of the ground, including seismic waves generated by earthquakes.
96. What is the hardest known natural substance on Earth?
Correct Answer: d) Diamond
Explanation:
Diamond is the hardest naturally occurring substance on Earth, scoring a perfect 10 on the Mohs scale of mineral hardness.
97. What is the normal body temperature of a healthy adult human?
Correct Answer: b) 37 degrees Celsius
Explanation:
The normal average human body temperature is generally accepted as 37 degrees Celsius (98.6 degrees Fahrenheit).
98. The filament of a traditional incandescent light bulb is typically made of:
Correct Answer: c) Tungsten
Explanation:
Tungsten is used for light bulb filaments because it has the highest melting point of all metals, allowing it to glow brightly without melting.
99. The scientific study of birds is known as:
Correct Answer: b) Ornithology
Explanation:
Ornithology is a branch of zoology that concerns the scientific study of birds.
100. What is the chemical symbol for gold?
Correct Answer: c) Au
Explanation:
The chemical symbol for gold is Au, derived from its Latin name 'Aurum'.
