11. Which planet is closest to the Sun?
Answer: Mercury. Located approximately 58 million kilometers (36 million miles) from the Sun, Mercury is a planet of extremes. Its temperature ranges from -180°C (-292°F) at night to 430°C (800°F) during the day, because it has virtually no atmosphere to retain heat. Paradoxically, Mercury is not the hottest planet in the solar system: that distinction belongs to Venus, whose dense CO₂ atmosphere creates such a powerful greenhouse effect that temperatures reach a constant 465°C (869°F). A year on Mercury lasts just 88 Earth days.
12. Who formulated the theory of relativity?
Answer: Albert Einstein. In 1905, the young 26-year-old physicist, working at the time as a patent clerk in Bern, Switzerland, published four revolutionary papers including one on special relativity that introduced the famous equation E=mc². Ten years later, in 1915, he completed his theory with general relativity, which redefined our understanding of gravity as a curvature of spacetime. These theories have been confirmed by numerous experiments and form the basis of GPS technology, nuclear energy, and our understanding of black holes.
Did you know? Einstein received the Nobel Prize in Physics in 1921, but not for relativity. He won it for his explanation of the photoelectric effect.
13. What gas do plants absorb during photosynthesis?
Answer: Carbon dioxide (CO₂). Photosynthesis is the process by which plants convert CO₂ and sunlight into glucose and oxygen. This mechanism is literally the lungs of our planet: forests and oceans (through phytoplankton) absorb approximately 50% of the CO₂ emitted by human activities. Without photosynthesis, the Earth's atmosphere would not contain the 21% oxygen necessary for our breathing.
Arts and Literature: Timeless Classics
Cultural and literary knowledge is a strong marker of general knowledge. These questions transcend eras and borders.
14. Who wrote "Les Miserables"?
Answer: Victor Hugo. Published in 1862, this monumental novel of more than 1,500 pages is considered one of the greatest masterpieces of world literature. It tells the story of Jean Valjean, a former convict seeking redemption, against the backdrop of social misery in 19th-century France. The musical adaptation, which premiered in London in 1985, is one of the longest-running shows in theatre history. The novel has been translated into virtually every language and continues to inspire film and television adaptations.
15. Which instrument has 88 keys?
Answer: The piano. It has 52 white keys and 36 black keys, spanning just over 7 octaves. The modern piano was invented by the Italian Bartolomeo Cristofori around 1700 in Florence. His major innovation was a hammer mechanism that allowed playing at different volumes (hence its full name: pianoforte, meaning "soft-loud" in Italian). Today, a Steinway concert grand piano contains approximately 12,000 parts and can cost over $150,000.
16. Who composed "The Four Seasons"?
Answer: Antonio Vivaldi. Composed in 1723, these four violin concertos are among the most performed and recognizable pieces of classical music in the world. Each concerto is accompanied by a sonnet describing the corresponding season. Vivaldi, nicknamed "The Red Priest" because of his red hair, was a violin virtuoso and a prolific composer with more than 500 concertos to his name. Despite his fame during his lifetime, his music fell into obscurity for two centuries before being rediscovered in the early 20th century.
17. What is the best-selling book in the world after the Bible?
Answer: Don Quixote by Miguel de Cervantes (1605). With more than 500 million copies sold, this novel is considered the first modern novel in Western literature. It tells the tragicomic adventures of a Spanish gentleman who, driven mad by reading too many chivalric romances, sets out on adventures with his faithful squire Sancho Panza. The expression "tilting at windmills," meaning to fight imaginary enemies, comes directly from this novel.
Nature: The Living World and Its Records
The natural world is full of records and astonishing facts. These questions are among the favorites of quiz enthusiasts.
18. What is the fastest land animal?
Answer: The cheetah. This extraordinary feline can reach 112 km/h (70 mph) in just three seconds, an acceleration that rivals a sports car. However, it can only maintain this speed for about 500 meters before risking overheating. Its extremely flexible spine, semi-retractable claws that act as cleats, and its long tail that serves as a rudder are all adaptations for speed. Sadly, the cheetah is classified as vulnerable: only about 7,000 individuals remain in the wild, primarily in Africa.
19. What is the largest ocean in the world?
Answer: The Pacific Ocean. With an area of 165.25 million km² (63.8 million sq mi), the Pacific is so vast that it covers more surface area than all the land on Earth combined. It stretches approximately 19,800 km from east to west and 15,500 km from north to south. The Pacific contains the deepest point in the oceans: the Mariana Trench, which reaches 10,994 meters (36,070 feet) below sea level. If Mount Everest were placed at the bottom of this trench, its summit would still be more than 2,000 meters below the surface.
20. What color are the blood cells that carry oxygen?
Answer: Red. Red blood cells (erythrocytes) owe their color to hemoglobin, an iron-rich protein that binds to oxygen to transport it throughout the body. An adult has approximately 25 trillion red blood cells, and the bone marrow produces about 2.4 million per second to replace those that die (average lifespan: 120 days). Surprisingly, the blood of horseshoe crabs is blue because it contains copper instead of iron.
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Go Further: Tips to Build Your General Knowledge
Now that you have explored these 20 essential questions, here are some tips to continue developing your general knowledge every day:
- Play quizzes regularly: Spaced repetition is the most effective learning method. A few minutes a day on QuizFury is all it takes.
- Read diverse articles: Alternate between science, history, geography, arts, and current events to cover all areas.
- Watch documentaries: Visual formats make it easier to memorize facts and dates.
- Join quiz nights: The social and competitive aspects strengthen engagement and retention.
- Write down surprising facts: Keeping an anecdote notebook helps fix knowledge in long-term memory.
Keep Testing Your Knowledge on QuizFury
How many of these 20 questions did you answer correctly? Whether you scored a perfect run or some answers surprised you, general knowledge is a field where we learn something new every day. The key is to stay curious, practice regularly, and never stop questioning the world around us.
