Getting your questions ready
Getting your questions ready
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50 free 10th Grade trivia questions with answers — trivia quiz, new questions added Aug 2026.
Tenth grade is the year school gets specific: the periodic table stops being a poster and starts being Mendeleev's gaps, Newton's laws explain why you lurch forward on a bus, and the quadratic formula, Mendel's pea plants and Magna Carta all arrive within a few months of each other. It is also the year most of us last knew any of it cold. These 50 questions follow a class 10 syllabus rather than a pub-quiz grab bag: biology, chemistry and physics make up the largest share, then maths (Pythagorean triples, the discriminant, perfect numbers), world and US history from Magna Carta to the Salt March, geography, civics, and the books a sophomore reads — The Great Gatsby, To Kill a Mockingbird, Lord of the Flies, Romeo and Juliet and Animal Farm. Every answer comes with a one-line explanation that adds something the textbook left out. Play it to see whether you would still pass, hand it to a student as a revision round, or print it for a classroom quiz.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which country, spanning eleven time zones and bordering fourteen others, is the largest on Earth?
Russia
Russia is the largest country on Earth yet only the ninth most populous, with just over 140 million people.
Q 02Which organ, the heaviest inside the human body, produces bile and stores around 100 g of glycogen?
Liver
The liver is the only human internal organ that regenerates naturally: as little as 25% of it can regrow into a whole liver.
Q 03Which organelle, the site of aerobic respiration, has its own DNA, inherited only from the mother?
Mitochondrion
The mitochondrion has a genome like a bacterium's, supporting the theory that it began as a free-living microbe engulfed by an early cell.
Q 04Which 1803 deal with Napoleon's France nearly doubled the size of the United States for $15 million?
Louisiana Purchase
The Louisiana Purchase worked out at less than three cents an acre, and Napoleon sold because war with Britain was imminent.
Q 05Which planet, the largest in the solar system, hosts the Great Red Spot, a storm tracked since the 1800s?
Jupiter
Jupiter's Great Red Spot has been observed continuously since 1878 and whips up winds of nearly 500 km/h.
Q 06Which explorer's fleet first circled the globe, though its commander was killed in the Philippines?
Magellan
Magellan left Spain with five ships and about 270 men; only the Victoria, under Elcano, completed the voyage, almost exactly three years later.
Q 07Which amendment to the US Constitution, ratified in December 1865, abolished slavery nationwide?
Thirteenth
The Thirteenth Amendment still allows involuntary servitude 'as a punishment for crime', the loophole behind convict leasing and prison labor.
Q 08Which mathematician, as a boy, reputedly summed 1 to 100 in seconds by pairing numbers into 101s?
Carl Friedrich Gauss
Carl Friedrich Gauss simply multiplied 50 by 101 to get 5050, the trick behind the arithmetic-series formula n(n+1)/2.
Q 09Which continent, though a polar desert, locks up about 70% of the world's fresh water as ice?
Antarctica
Antarctica's ice averages 1.9 km thick and would raise global sea levels by almost 60 meters if it all melted.
Q 10Which novella satirizing Stalin's Soviet Union ends with pigs walking upright and carrying whips?
Animal Farm
Animal Farm's final commandment reads 'All animals are equal, but some animals are more equal than others', and the pigs end up indistinguishable from the men.
Q 11Which element, first identified as a distinct gas by Henry Cavendish, makes up 75% of normal matter?
Hydrogen
Hydrogen was Cavendish's 'inflammable air'; Lavoisier later named it from the Greek for 'water-former' after showing it burns to make water.
Q 12Which photosynthetic pigment absorbs red and blue light but reflects the wavelengths in between?
Chlorophyll
Chlorophyll is why autumn leaves turn yellow: as it breaks down, the carotenoids that were there all summer finally show through.
Q 13Which property, the subject of Newton's first law, throws bus riders forward when the driver brakes?
Inertia
Inertia is the tendency of a mass to resist any change in its motion, which is why Newton's first law is also called the principle of inertia.
Q 21Which eye defect, where distant objects focus in front of the retina, does a diverging lens correct?
Myopia
Myopia is the most common eye disorder, affecting an estimated 1.5 billion people — about 22% of the world — and rates have climbed since the 1950s.
Q 22Which leaf pores, usually more numerous on the underside, open and close to control gas exchange?
Stomata
Stomata are flanked by two guard cells that bow apart as they swell with water, opening the pore, and relax to close it again.
Q 23Which gas, released when baking soda meets vinegar, turns clear limewater milky?
Carbon dioxide
Carbon dioxide reacts with the calcium hydroxide in limewater to precipitate insoluble calcium carbonate, the same compound as chalk.
Q 14Which law, set out by a German physicist in 1827, makes current in a wire proportional to voltage?
Ohm's law
Ohm's law is the reason resistance is measured in ohms: Georg Ohm found the rule by testing wires of different lengths in simple circuits.
Q 15On the pH scale, what value marks neutral pure water at 25 °C, with acids below it and bases above?
7
A pH of 7 is neutral because H+ and OH− ions are present in equal amounts, and each step on the scale is a tenfold change in acidity.
Q 16What is the approximate speed of light in a vacuum, the constant c in Einstein's equation E = mc²?
300,000 km/s
Light covers about 300,000 km/s, so the sunlight reaching Earth left the Sun a little over eight minutes earlier.
Q 17Mendel's monohybrid cross of two heterozygous pea plants gave what ratio of dominant to recessive traits?
3:1
The 3:1 ratio appears because a recessive trait shows only when both alleles are recessive, which happens in one offspring in four.
Q 18Which brain structure, tucked under the cerebral hemispheres, coordinates fine movement and balance?
Cerebellum
The cerebellum packs in more neurons than the rest of the brain combined while taking up only about 10% of its volume.
Q 19Which alkali metal, atomic number 11, is stored under oil and is soft enough to cut with a knife?
Sodium
Sodium's best-known compound is table salt, NaCl, yet the pure metal is so reactive it has to be kept in oil or an inert gas.
Q 20Which optical effect, far stronger at short wavelengths, makes the daytime sky blue and sunsets red?
Rayleigh scattering
Rayleigh scattering varies inversely with the fourth power of wavelength, so blue light is scattered far more than red as sunlight crosses the air.
Q 24Whose periodic table left gaps for undiscovered elements, rightly predicting gallium and germanium?
Dmitri Mendeleev
Dmitri Mendeleev called them eka-aluminium and eka-silicon, and he also foresaw scandium; his 1869 table ran by atomic weight, not atomic number.
Q 25Which of DNA's four bases is missing from RNA, where uracil takes its place?
Thymine
Thymine is simply uracil with a methyl group bolted on, which is why chemists also call it 5-methyluracil.
Q 26A right triangle has legs of 8 and 15; what hypotenuse completes this primitive Pythagorean triple?
17
17 completes the 8-15-17 triple; the Babylonian tablet Plimpton 322 listed such triples around 1800 BC, long before Pythagoras.
Q 27What value of the discriminant b² − 4ac gives a quadratic equation exactly one repeated real root?
Zero
A zero discriminant means the parabola just touches the x-axis at a single point, so the two roots collapse into one double root.
Q 28What is the sum of the interior angles of a hexagon, the shape bees use for honeycomb cells?
720°
720° split six ways gives the 120° corners that let regular hexagons tile a plane with no gaps, three meeting at every vertex.
Q 29Which Greek mathematician's treatise Elements proved that there are infinitely many prime numbers?
Euclid
Euclid's proof still works: multiply any finite list of primes together, add one, and the result has a prime factor missing from the list.
Q 30In a 30-60-90 right triangle, the side opposite the 30° angle is what fraction of the hypotenuse?
1/2
1/2 follows because a 30-60-90 triangle is half an equilateral triangle, which is also why sin 30° equals exactly one half.