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Science GK Questions - General Knowledge

"Discover a detailed set of Science GK Questions - General Knowledge ranging from physics to chemistry, biology, space, and beyond! Ideal for competitive exams, quizzes, and overall general knowledge enhancement. Check your science IQ with these thought-provoking and educational questions!"

Science GK Questions - General Knowledge

Science Gk Questions - General Knowledge - Father of Science GK

1. Who is known as the Father of Zoology?  

a) Charles Darwin  

b) Gregor Mendel  

c) Aristotle   

d) Louis Pasteur  

 Answer: Aristotle  

Explanation: Aristotle made significant contributions to the classification and study of animals. He classified animals into groups based on their characteristics and wrote extensively about their anatomy and behavior.

 

 2. Who is regarded as the Father of Genetics?  

a) William Bateson  

b) Gregor Johann Mendel   

c) H. J. Muller  

d) Hugo de Vries  

 Answer: Gregor Johann Mendel  

Explanation: Mendel discovered the fundamental laws of inheritance through experiments on pea plants, establishing dominant and recessive traits, forming the basis of modern genetics.

 

 3. Who discovered that radiation causes genetic mutations and is known as the Father of Radiation Genetics?  

a) H. J. Muller   

b) William Bateson  

c) Gregor Mendel  

d) Francis Galton  

 Answer: H. J. Muller  

Explanation: Hermann Joseph Muller demonstrated that exposure to Xrays could cause genetic mutations, paving the way for further research in genetics and medical sciences.

 

 4. Who coined the term "Genetics" and is known as the Father of Modern Genetics?  

a) Gregor Mendel  

b) William Bateson   

c) Hugo de Vries  

d) Edward Jenner  

 Answer: William Bateson  

Explanation: Bateson was the first to use the term "Genetics" and promoted Mendel’s findings, helping to establish genetics as a separate scientific field.

 

 5. Who is called the Father of Modern Anatomy?  

a) Andreas Vesalius   

b) William Harvey  

c) Hippocrates  

d) Edward Jenner  

 Answer: Andreas Vesalius  

Explanation: Vesalius’s detailed human dissections and publication De Humani Corporis Fabrica revolutionized the study of human anatomy.

 

 6. Who first described the circulatory system and is known as its father?  

a) William Harvey   

b) Hippocrates  

c) Carolus Linnaeus  

d) Robert Koch  

 Answer: William Harvey  

Explanation: Harvey discovered that blood circulates continuously throughout the body, disproving earlier beliefs that the liver produces new blood.

 

 7. Who is the Father of Taxonomy?  

a) Carolus Linnaeus   

b) Theophrastus  

c) Gregor Mendel  

d) Leonardo da Vinci  

 Answer: Carolus Linnaeus  

Explanation: Linnaeus developed the Binomial Nomenclature system, which is still used today to classify living organisms.

 

 8. Who is known as the Father of Medicine?  

a) Hippocrates   

b) Andreas Vesalius  

c) Edward Jenner  

d) William Harvey  

 Answer: Hippocrates  

Explanation: Hippocrates emphasized natural causes of diseases and ethical medical practices, introducing the Hippocratic Oath, still used by doctors today.

 

 9. Who developed the first vaccine and is called the Father of Immunology?  

a) Robert Koch  

b) Edward Jenner   

c) Louis Pasteur  

d) Gregor Mendel  

 Answer: Edward Jenner  

Explanation: Jenner developed the first smallpox vaccine, laying the foundation for modern immunology and vaccine development.

 

 10. Who proposed Germ Theory and is known as the Father of Microbiology?  

a) Robert Koch  

b) Louis Pasteur   

c) Edward Jenner  

d) H. J. Muller  

 Answer: Louis Pasteur  

Explanation: Pasteur’s Germ Theory proved that microorganisms cause diseases. He also developed pasteurization to prevent bacterial contamination in food.

 

 11. Who proposed the Mutation Theory and is considered the Father of Mutation Genetics?  

a) Hugo de Vries   

b) Gregor Mendel  

c) William Bateson  

d) Thomas Addison  

 Answer: Hugo de Vries  

Explanation: De Vries introduced the Mutation Theory, explaining how sudden genetic changes lead to new variations in species.

 

 12. Who is called the Father of Microscopy?  

a) Marcello Malpighi   

b) Louis Pasteur  

c) Robert Koch  

d) Carolus Linnaeus  

 Answer: Marcello Malpighi  

Explanation: Malpighi used the microscope to study tissues and cells, making significant contributions to histology and anatomy.

 

 13. Who discovered the bacteria responsible for tuberculosis and cholera and is known as the Father of Bacteriology?  

a) Robert Koch   

b) Louis Pasteur  

c) Edward Jenner  

d) William Harvey  

 Answer: Robert Koch  

Explanation: Koch discovered Mycobacterium tuberculosis and Vibrio cholerae, establishing the cause of tuberculosis and cholera.

 

 14. Who first studied fossils and is considered the Father of Paleontology?  

a) Leonardo da Vinci   

b) Carolus Linnaeus  

c) Theophrastus  

d) Robert Koch  

 Answer: Leonardo da Vinci  

Explanation: Da Vinci studied and correctly identified fossils as the remains of ancient organisms, contributing to the understanding of Earth's history.

 

 15. Who is called the Father of Botany?  

a) Theophrastus   

b) Carolus Linnaeus  

c) William Harvey  

d) Gregor Mendel  

 Answer: Theophrastus  

Explanation: Theophrastus wrote Enquiry into Plants, which was the first systematic study of plant biology.

 

 16. Who studied plant diseases and is regarded as the Father of Plant Pathology?  

a) A. J. Butler   

b) Theophrastus  

c) Louis Pasteur  

d) Robert Koch  

 Answer: A. J. Butler  

Explanation: Butler classified plant diseases and proposed solutions to improve agricultural productivity.

 

 17. Who is known as the Father of Plant Physiology?  

a) Stephen Hales   

b) Theophrastus  

c) Gregor Mendel  

d) Hugo de Vries  

 Answer: Stephen Hales  

Explanation: Hales discovered how water moves in plants and studied their respiration and growth.

 

 18. Who discovered bacteriophages and is considered their father?  

a) Twort & d'Herelle   

b) Robert Koch  

c) Louis Pasteur  

d) Edward Jenner  

 Answer: Twort & d’Herelle  

Explanation: They discovered bacteriophages, viruses that infect bacteria, which later became useful in treating bacterial infections.

 

 19. Who is considered the Father of Eugenics?  

a) Francis Galton   

b) Gregor Mendel  

c) William Bateson  

d) Hugo de Vries  

 Answer: Francis Galton  

Explanation: Galton introduced the idea of Eugenics, the study of improving the genetic quality of human populations.

 

 20. Who is called the Father of Gerontology, the study of aging?  

a) Vladimir Korenchevsky   

b) Francis Galton  

c) Robert Koch  

d) Carolus Linnaeus  

 Answer: Vladimir Korenchevsky  

Explanation: Korenchevsky conducted extensive research on aging, helping to develop better health policies for the elderly.

Science Gk Questions - General Knowledge – Cell Based GK

21. Which is the control center of the cell?
 A) Mitochondria
 B) Cell Membrane
 C) Nucleus
 D) Cytoplasm
 Answer: C) Nucleus
 Explanation: The nucleus is the control center of the cell as it stores the DNA and controls all the activities of the cell.

 22. What is called the "powerhouse" of the cell?
 A) Ribosome
 B) Mitochondria
 C) Chloroplast
 D) Cytoplasm
 Answer: B) Mitochondria
 Explanation: Mitochondria generate energy (ATP) for the cell, hence it is called the "power house of the cell".

 23.Which is the outer membrane of the cell called?
 A) Cell Wall
 B) Cell Membrane
 C) Cytoplasm
 D) Nuclear Membrane (Nuclear Membrane)
 Answer: B) Cell Membrane
 Explanation: The cell membrane is the outer layer of the cell that protects and controls the internal parts.
 
 24. What are the types of plastids?
 A) Chloroplast
 B) Colorless plastid (Leucoplast)
 C) Chromoplast
 D) All of the above
 Answer: D) All of the above
 Explanation: Plastids are of three types  chloroplast (provides green color), leucoplast (storage), and chromoplast (responsible for other colors).
 
 25. Which organelle in the cell acts as the "brain"?
 A) Mitochondria
 B) Nucleus
 C) Ribosome
 D) Lysosome
 Answer: B) Nucleus
 Explanation: The nucleus controls the genetic material (DNA) of the cell and directs all the activities of the cell, hence it is called the "brain of the cell".
 
 26.Which is the plasma membrane made of?
 A) Protein
 B) Phospholipid
 C) Carbohydrate
 D) Glucose
 Answer: B) Phospholipid
 Explanation: The plasma membrane is mainly made up of a phospholipid bilayer, which controls the movement of substances into and out of the cell.
 
 27.Which is found inside the nucleus?
 A) Ribosome
 B) Nucleolus
 C) Mitochondria
 D) Lysosome
 Answer: B) Nucleolus
 Explanation: The nucleolus is found inside the nucleus and is responsible for the formation of ribosomes.
 
 28.In which part of the cell is water and mineral salts located?
 A) Cytoplasm
 B) Lysosome
 C) Mitochondria
 D) Cell Membrane
 Answer: A) Cytoplasm
 Explanation: Cytoplasm is a gellike material in which water, mineral salts and other substances are suspended.
 
 29.What organelle is responsible for protein synthesis?
 A) Mitochondria
 B) Lysosome
 C) Ribosome
 D) Nucleolus
 Answer: C) Ribosome
 Explanation: Ribosomes are responsible for protein synthesis, which is essential for cell development and functioning.
 
 30.Where does photosynthesis take place?
 A) Mitochondria
 B) Chloroplast
 C) Ribosome
 D) Cytoplasm
 Answer: B) Chloroplast
 Explanation: Chloroplast is found in plants and it plays a major role in the process of photosynthesis, from which plants make food (glucose).
 
 31.What organelle is responsible for removing waste products?
 A) Mitochondria
 B) Lysosome
 C) Cell Membrane
 D) Ribosome
 Answer: B) Lysosome
 Explanation: The lysosome is called the "waste disposal center of the cell" because it functions to digest and remove unwanted substances.
 
32.What is the name of the green plastid?
 A) Chloroplast
 B) Leucoplast
 C) Chromoplast
 D) Ribosome
 Answer: A) Chloroplast
 Explanation: Chloroplast is a green plastid which appears green due to the presence of chlorophyll pigment and helps in photosynthesis.
 
 33.Where is DNA located in the cell?
 A) Mitochondria
 B) Nucleus
 C) Ribosome
 D) Cytoplasm
 Answer: B) Nucleus
 Explanation: DNA is found in the nucleus of a cell, which stores genetic information and controls cell functions.
 
 34. Which structure is actively involved in cell division?
 A) Mitochondria
 B) Lysosome
 C) Mitotic Spindle
 D) Ribosome
 Answer: C) Mitotic Spindle
 Explanation: Mitotic spindle is made up of microtubules and it helps in proper distribution of chromosomes during cell division.
 
 35.What is called the "skeleton of the cell"?
 A) Cytoskeleton
 B) Mitochondria
 C) Cell Membrane
 D) Nucleus
 Answer: A) Cytoskeleton
 Explanation: Cytoskeleton is a framework that helps the cell to maintain its shape and in proper movement of organelles.
 
 36.What is called the "control center" of the cell?
 A) Nucleus
 B) Mitochondria
 C) Lysosome
 D) Cytoplasm
 Answer: A) Nucleus
 Explanation: The nucleus controls all the functions of the cell and contains the genetic material (DNA).
 
37. Which organ produces energy in the cell?
 A) Nucleus
 B) Mitochondria
 C) Lysosome
 D) Chloroplast
 Answer: B) Mitochondria
 Explanation: Mitochondria generate ATP (Adenosine Triphosphate) energy for the cell, which is required for various activities of the cell.
 
 38. Where is the process of protein synthesis?
 A) Mitochondria
 B) Ribosome
 C) Nucleus
 D) Lysosome
 Answer: B) Ribosome
 Explanation: Ribosome completes the process of protein synthesis inside the cell.
 
39.Where does photosynthesis take place?
 A) Mitochondria
 B) Chloroplast
 C) Ribosome
 D) Nucleolus
 Answer: B) Chloroplast
 Explanation: Chlorophyll is found in chloroplast, which is necessary for the process of photosynthesis.
 
40. Cell wall is found in which cells?
 A) In Animal Cells
 B) In human cells
 C) In Plant Cells
 D) All Types of Cells
 Answer: C) Plant Cells
 Explanation: Only plant cells have a cell wall, which provides rigidity and structural support to the cell.

 

 41. What is the main source of energy in cells?
 A) Protein
 B) Glucose
 C) Fat
 D) ATP
 Answer: B) Glucose
 Explanation: Glucose is the main source of energy in cells. It is converted into ATP energy through cellular respiration.

 

 42. Most of the water is found in which cell organ?
 A) Cytoplasm
 B) Nucleus
 C) Vacuole
 D) Lysosome
 Answer: C) Vacuole
 Explanation: A large central vacuole in plant cells stores water and other nutrients, which help maintain the structure of the cell.

 

 43. Kisese hoti buni hai in plant cells?
 A) Glucose
 B) Cellulose
 C) Protein
 D) Fat
 Answer: B) Cellulose
 Explanation: The cell wall of plants is made of cellulose, which gives it rigidity and strength.

 

 44. Which organ destroys toxins in cells?
 A) Mitochondria
 B) Ribosome
 C) Lysosome
 D) Endoplasmic Reticulum
 Answer: C) Lysosome
 Explanation: Lysosome helps in the destruction of cellular waste products and toxins. It is also called "cell cleaner".

 45. What is the role of ribosomes in protein synthesis?
 A) Helps in cell division
 B) produces energy
 C) Produces protein
 D) Protects cells
 Answer: C) Protein Synthesis
 Explanation: Ribosomes are responsible for protein synthesis in cells. They combine amino acids to form proteins based on the genetic instructions of the cell.

 46. What is the main function of cell membrane?
 A) Energy production
 B) Storage of genetic material
 C) Cell control and protection
 D) Aid in cell division
 Answer: C) Control and Protection of the Cell
 Explanation: The cell membrane separates the cell from the external environment and controls the exchange of substances within the cell.

 

 47. Which cell organ's function is to maintain the internal balance of the cell?
 A) Lysosome
 B) Endoplasmic Reticulum
 C) Chloroplast
 D) Mitochondria
 Answer: B) Endoplasmic Reticulum
 Explanation: Endoplasmic reticulum transports various substances within the cell and helps maintain the balance in the cell.

 48. Kis anga mein keshita ki vasa ka sintha hota hai?
 A) Ribosome
 B) Mitochondria
 C) Endoplasmic Reticulum
 D) Nucleus
 Answer: C) Endoplasmic Reticulum
 Explanation: Smooth ER is responsible for fat and lipid synthesis.

 

 49. Which cell organ produces ATP?
 A) Ribosome
 B) Mitochondria
 C) Lysosome
 D) Chloroplast
 Answer: B) Mitochondria
 Explanation: Mitochondria produce ATP (Adenosine Triphosphate) energy, hence it is called the "powerhouse of the cell".
 
 50. Why is a cell called a "cooking organ"?
 A) Mitochondria
 B) Chloroplast
 C) Ribosome
 D) Vacuole
 Answer: B) Chloroplast
 Explanation: Photosynthesis takes place in the chloroplast, from which plants make their food, hence it is called "cell's kitchen".
 
51. Which organ plays a major role during cell division?
 A) Nucleus
 B) Centrosome
 C) Chloroplast
 D) Cytoplasm
 Answer: B) Centrosome
 Explanation: Centrosome helps in cell division by forming spindle fibers.

 52. Where are the major residues and waste products stored in the cell?
 A) Nucleus
 B) Mitochondria
 C) Vacuole
 D) Lysosome
 Answer: C) Vacuole
 Explanation: Vacuole stores water, mineral salts and waste materials in the cell.
 
 53. What is the function of blood cells and proteins?
 A) Mitochondria
 B) Ribosome
 C) Endoplasmic Reticulum
 D) Lysosome
 Answer: B) Ribosome
 Explanation: Ribosomes carry out protein synthesis in cells, including blood proteins.
 
 54. Nabhik ki bahri paktar ko kya kaha jaata hai?
 A) Cell Membrane
 B) Cytoplasm
 C) Nuclear Membrane (Nuclear Membrane)
 D) Mitochondria
 Answer: C) Nuclear Membrane
 Explanation: The nuclear membrane is the membrane that surrounds the nucleus, separating it from other parts of the cell.
 
 55. Which organ plays a major role in the production of cell energy?
 A) Ribosome
 B) Mitochondria
 C) Chloroplast
 D) Lysosome
 Answer: B) Mitochondria
 Explanation: Mitochondria works to convert glucose into ATP energy in the cell, hence it is called "Powerhouse of the Cell".
 
 56. What is the function of vacuole?
 A) Energy production
 B) cell division
 C) Collection and disposal of waste
 D) protein synthesis
 Answer: C) Storage and Waste Disposal
 Explanation: Vacuole stores nutrients and waste materials in the cell and also helps in their elimination process.
 
 57. Which cell is only found in plants?
 A) Mitochondria
 B) Lysosome
 C) Chloroplast
 D) Ribosome
 Answer: C) Chloroplast
 Explanation: Chloroplast is found only in plant cells and plays an important role in the process of photosynthesis.

 58. What are the structural and functional basis of cells?
 A) Cell Wall
 B) Cell Membrane
 C) Cell Organelles
 D) Nucleus
 Answer: C) Cell Organelles
 Explanation: Various organelles of the cell like mitochondria, ribosomes, endoplasmic reticulum etc. form the structural and functional basis.

 59. What is the function of flagella?
 A) Providing movement to the cell
 B) Assist in cell division
 C) generate energy
 D) carry out protein synthesis
 Answer: A) Locomotion and Movement
 Explanation: A flagella is a long, thin structure that helps cells move from one place to another.

 60. How are water and salts converted into cells?
 A) ATP
 B) Nucleic acid
 C) Different types of chemical substances
 D) Amino acids
 Answer: C) Various Types of Chemical Substances
 Explanation: Water and salts take part in many biochemical reactions in the cell and are converted into various essential substances.
 

Science Gk Questions - General Knowledge – Solar System GK

 The Solar System is a fascinating part of our universe, filled with planets, moons, asteroids, and mysteries waiting to be explored. Whether you're a student preparing for competitive exams or just a space enthusiast, testing your knowledge with General Knowledge (GK) questions can be both fun and educational!

61. Which planet is the largest in our solar system?  
A) Saturn (शनि)  
B) Jupiter (वृहस्पति)  
C) Neptune (वरुण)  
D) Earth (पृथ्वी)  
Answer: B) Jupiter (वृहस्पति)  
Explanation: Jupiter is the largest planet in the solar system, with a diameter of about 139,820 km. Its massive size allows it to have a strong gravitational pull and numerous moons.
 
62. Which planet is the smallest in our solar system?  
A) Mercury (बुध)  
B) Mars (मंगल)  
C) Venus (शुक्र)  
D) Pluto (प्लूटो)  
Answer: A) Mercury (बुध)  
Explanation: Mercury, with a diameter of about 4,880 km, is the smallest planet. Pluto is no longer classified as a planet but as a dwarf planet.
 
63. Which planet is closest to the Sun?  
A) Venus (शुक्र)  
B) Earth (पृथ्वी)  
C) Mercury (बुध)  
D) Mars (मंगल)  
Answer: C) Mercury (बुध)  
Explanation: Mercury orbits the Sun at an average distance of about 58 million km, making it the closest planet to our star.
 
64. Which planet is the farthest from the Sun?  
A) Uranus (अरुण)  
B) Neptune (वरुण)  
C) Saturn (शनि)  
D) Jupiter (वृहस्पति)  
Answer: B) Neptune (वरुण)  
Explanation: Neptune is the farthest planet from the Sun, with an average distance of about 4.5 billion km.
 
65.Which is the largest moon in our solar system?  
A) Titan (टाइटन)  
B) Ganymede (गैनिमीड)  
C) Earth’s Moon (चंद्रमा)  
D) Callisto (कैलिस्टो)  
Answer: B) Ganymede (गैनिमीड)  
Explanation: Ganymede, a moon of Jupiter, is the largest in the solar system, with a diameter of 5,268 km—larger than even the planet Mercury.
 
66. Which is the smallest moon in our solar system?  
A) Deimos (डीमोस)  
B) Phobos (फोबोस)  
C) Europa (यूरोपा)  
D) Io (आयो)  
Answer: A) Deimos (डीमोस)  
Explanation: Deimos, a moon of Mars, is the smallest known moon in the solar system, with a diameter of about 12 km.

67. Which planet appears the brightest from Earth?  
A) Jupiter (वृहस्पति)  
B) Venus (शुक्र)  
C) Mars (मंगल)  
D) Mercury (बुध)  
Answer: B) Venus (शुक्र)  
Explanation: Venus is the brightest planet due to its reflective cloud cover and proximity to Earth.
 
68. Which star is the brightest in the night sky?  
A) Polaris (ध्रुव तारा)  
B) Betelgeuse (बीटलजूस)  
C) Sirius (साइरस)  
D) Vega (वेगा)  
Answer: C) Sirius (साइरस)  
Explanation: Sirius, in the constellation Canis Major, is the brightest star visible from Earth, with an apparent magnitude of -1.46.
 
69. Which planet has the most moons?  
A) Jupiter (वृहस्पति)  
B) Saturn (शनि)  
C) Uranus (अरुण)  
D) Neptune (वरुण)  
Answer: B) Saturn (शनि)  
Explanation: Saturn currently holds the record for the most confirmed moons, with over 145 (as of recent counts), surpassing Jupiter.
 
70. Which planet is the heaviest in our solar system?  
A) Earth (पृथ्वी)  
B) Neptune (वरुण)  
C) Jupiter (वृहस्पति)  
D) Saturn (शनि)  
Answer: C) Jupiter (वृहस्पति)  
Explanation: Jupiter is the heaviest planet, with a mass of about 1.9 × 10²⁷ kg, due to its large size and dense composition.
 
71. Which planet appears red in the night sky?  
A) Venus (शुक्र)  
B) Mars (मंगल)  
C) Jupiter (वृहस्पति)  
D) Saturn (शनि)  
Answer: B) Mars (मंगल)  
Explanation: Mars appears red due to iron oxide (rust) on its surface, which reflects sunlight in a reddish hue.
 
72. Which planet is the coldest in our solar system?  
A) Uranus (अरुण)  
B) Neptune (वरुण)  
C) Saturn (शनि)  
D) Jupiter (वृहस्पति)  
Answer: B) Neptune (वरुण)  
Explanation: Neptune, being the farthest from the Sun, has an average temperature of about -201°C, making it the coldest planet.
 
73. Which planet is closest to Earth?  
A) Mars (मंगल)  
B) Venus (शुक्र)  
C) Mercury (बुध)  
D) Jupiter (वृहस्पति)  
Answer: B) Venus (शुक्र)  
Explanation: Venus is Earth’s closest planetary neighbor, with an average distance of about 41 million km.
 
74.What is the moon of Earth commonly called?  
A) Titan (टाइटन)  
B) Earth’s Moon (चंद्रमा)  
C) Ganymede (गैनिमीड)  
D) Phobos (फोबोस)  
Answer: B) Earth’s Moon (चंद्रमा)  
Explanation: Earth’s only natural satellite is called the Moon (or चंद्रमा in Hindi), with a diameter of about 3,474 km.
 
75. Which planet is known as Earth’s sister planet?  
A) Venus (शुक्र)  
B) Mars (मंगल)  
C) Mercury (बुध)  
D) Jupiter (वृहस्पति)  
Answer: A) Venus (शुक्र)  
Explanation: Venus is called Earth’s sister planet due to its similar size, mass, and composition, though its extreme conditions differ vastly.
 
76. Which planet has the longest day in the solar system?  
A) Jupiter (वृहस्पति)  
B) Venus (शुक्र)  
C) Mercury (बुध)  
D) Mars (मंगल)  
Answer: B) Venus (शुक्र)  
Explanation: Venus has the longest day, lasting about 243 Earth days, because it rotates very slowly on its axis—slower than it takes to orbit the Sun (225 Earth days).
 
77. Which planet is most famously known for its prominent ring system?  
A) Jupiter (वृहस्पति)  
B) Uranus (अरुण)  
C) Saturn (शनि)  
D) Neptune (वरुण)  
Answer: C) Saturn (शनि)  
Explanation: Saturn is renowned for its extensive and visible ring system, made of ice, rock, and dust, observable even with small telescopes.
 
78. Which planet is the hottest in our solar system?  
A) Mercury (बुध)  
B) Venus (शुक्र)  
C) Mars (मंगल)  
D) Jupiter (वृहस्पति)  
Answer: B) Venus (शुक्र)  
Explanation: Venus, despite being farther from the Sun than Mercury, is the hottest planet at about 460°C due to its thick greenhouse-effect-causing atmosphere.
 
79. Which planet has the shortest day in the solar system?  
A) Jupiter (वृहस्पति)  
B) Saturn (शनि)  
C) Earth (पृथ्वी)  
D) Mars (मंगल)  
Answer: A) Jupiter (वृहस्पति)  
Explanation: Jupiter’s day lasts about 9.9 hours, the shortest due to its rapid rotation as a gas giant.
 
80. Which is the second largest planet in the solar system?  
A) Saturn (शनि)  
B) Neptune (वरुण)  
C) Uranus (अरुण)  
D) Earth (पृथ्वी)  
Answer: A) Saturn (शनि)  
Explanation: Saturn, with a diameter of about 116,460 km, is the second largest planet after Jupiter.
 
81. Which planet has the most extreme axial tilt?  
A) Jupiter (वृहस्पति)  
B) Uranus (अरुण)  
C) Mars (मंगल)  
D) Venus (शुक्र)  
Answer: B) Uranus (अरुण)  
Explanation: Uranus has an axial tilt of about 98°, causing it to rotate on its side, likely due to a massive ancient collision.
 
82. Which planet has no known moons?  
A) Mercury (बुध)  
B) Mars (मंगल)  
C) Jupiter (वृहस्पति)  
D) Saturn (शनि)  
Answer: A) Mercury (बुध)  
Explanation: Mercury, along with Venus, has no natural moons, likely due to its proximity to the Sun’s gravitational influence.
 
 83. Which planet hosts the largest volcano in the solar system?  
A) Earth (पृथ्वी)  
B) Mars (मंगल)  
C) Venus (शुक्र)  
D) Jupiter (वृहस्पति)  
Answer: B) Mars (मंगल)  
Explanation: Olympus Mons on Mars is the largest volcano, standing about 22 km high—three times the height of Mount Everest.
 
 84. Which planet is known for having the most violent storms?  
A) Jupiter (वृहस्पति)  
B) Saturn (शनि)  
C) Neptune (वरुण)  
D) Uranus (अरुण)  
Answer: C) Neptune (वरुण)  
Explanation: Neptune has the strongest winds in the solar system, reaching speeds of up to 2,100 km/h, driving violent storms.
 
 85. Which planet features the Great Red Spot, a massive storm?  
A) Saturn (शनि)  
B) Jupiter (वृहस्पति)  
C) Neptune (वरुण)  
D) Mars (मंगल)  
Answer: B) Jupiter (वृहस्पति)  
Explanation: The Great Red Spot is a giant storm on Jupiter, observed for over 300 years, larger than Earth itself.
 
 86. Which planet has the thinnest atmosphere?  
A) Mercury (बुध)  
B) Mars (मंगल)  
C) Venus (शुक्र)  
D) Earth (पृथ्वी)  
Answer: A) Mercury (बुध)  
Explanation: Mercury’s atmosphere is extremely thin (an exosphere), composed of atoms blasted off its surface by solar wind.
 
 87. Which planet is the second brightest in the night sky?  
A) Jupiter (वृहस्पति)  
B) Mars (मंगल)  
C) Saturn (शनि)  
D) Mercury (बुध)  
Answer: A) Jupiter (वृहस्पति)  
Explanation: After Venus, Jupiter is the second brightest planet due to its size and reflective clouds, despite being farther from Earth.

88. Which planet takes the longest to orbit the Sun?  
A) Uranus (अरुण)  
B) Neptune (वरुण)  
C) Saturn (शनि)  
D) Jupiter (वृहस्पति)  
Answer: B) Neptune (वरुण)  
Explanation: Neptune’s orbit takes about 164.8 Earth years, the longest as it’s the farthest planet from the Sun.

89. Which planet contains the most water by volume?  
A) Earth (पृथ्वी)  
B) Jupiter (वृहस्पति)  
C) Saturn (शनि)  
D) Neptune (वरुण)  
Answer: A) Earth (पृथ्वी)  
Explanation: Earth has the most liquid water on its surface (about 71%), though gas giants like Jupiter may have water in vapor form deep within

 90. Which planet was discovered through mathematical predictions rather than observation?  
A) Uranus (अरुण)  
B) Neptune (वरुण)  
C) Saturn (शनि)  
D) Jupiter (वृहस्पति)  
Answer: B) Neptune (वरुण)  
Explanation: Neptune was discovered in 1846 based on mathematical calculations by Urbain Le Verrier, who predicted its position due to gravitational effects on Uranus.