Science Olympiad : General Science MCQ set - 1
Q. What layer of Earth protects us from ultraviolet radiation and harmful solar rays ?
Ans: Ozone layer
Explanation: The ozone layer is found in the stratosphere. It absorbs almost all harmful ultraviolet (UV) rays from the Sun. Without this protective layer, UV radiation would damage human skin, plants, animals, and disrupt life on Earth.
Q. What device is used to measure atmospheric pressure ?
Ans: Barometer
Explanation: A barometer records atmospheric pressure, helping predict weather changes. High pressure means clear weather, while low pressure indicates rain or storms. It is an essential instrument for meteorologists.
Q. Which gas is commonly used in fluorescent lamps for lighting ?
Ans: Mercury vapor
Explanation: Fluorescent lamps contain mercury vapor. When electricity passes through it, the vapor produces ultraviolet light, which then strikes the phosphor coating inside the tube to create bright visible light.
Q. What is the chemical formula for baking soda ?
Ans: Sodium bicarbonate (NaHCO₃)
Explanation: Baking soda is sodium bicarbonate. It produces carbon dioxide gas when heated or mixed with acids like vinegar, which makes dough rise and become fluffy.
Q. Which moon is Earth's only natural satellite ?
Ans: The Moon
Explanation: The Moon orbits Earth and is its only natural satellite. It affects ocean tides, stabilizes Earth’s rotation, and reflects sunlight, making it shine at night.
Q. Which process converts nitrogen gas into a form usable by plants ?
Ans: Nitrogen fixation
Explanation: Nitrogen fixation changes atmospheric nitrogen (N₂) into nitrates or ammonia. Soil bacteria, lightning, and some plants perform this process, making nitrogen available for plant growth.
Q. At approximately what speed does sound travel in air at sea level ?
Ans: 343 m/s
Explanation:
Sound travels around 343 meters per second in air at room temperature. Its speed changes with temperature, humidity, and pressure—faster in warm air, slower in cold air.
Q. Which vitamin is synthesized in the skin when exposed to sunlight ?
Ans: Vitamin D
Explanation: Sunlight triggers the skin to produce Vitamin D. This vitamin helps absorb calcium, strengthens bones, and supports the immune system. Lack of sunlight can cause deficiency.
39. What phenomenon makes the sky appear blue ?
Ans: Rayleigh scattering
Explanation: Rayleigh scattering happens when sunlight hits tiny air molecules. Blue light scatters more than red light because it has a shorter wavelength, making the sky look blue during daytime.
Q. What gas is used to fill balloons to make them float ?
Ans: Helium
Explanation: Helium is lighter than air and non-flammable. Balloons filled with helium float because the gas is less dense than the surrounding atmosphere, lifting the balloon.
Q. What is the term for a substance changing directly from a solid to a gas ?
Ans: Sublimation
Explanation: Sublimation is the direct change of a solid into a gas without passing through the liquid state. Dry ice (solid CO₂) is a common example—it turns straight into gas.
Q. Which instrument is used to measure blood pressure ?
Ans: Sphygmomanometer
Explanation: A sphygmomanometer measures systolic and diastolic blood pressure using an inflatable cuff and gauge. Doctors use it to check heart health and diagnose hypertension.
Q. Who is considered the father of genetics ?
Ans: Gregor Mendel
Explanation: Gregor Mendel studied pea plants and discovered how traits pass from parents to offspring. His work laid the foundation of genetics, involving dominant and recessive genes.
Q. What is the liquid part of human blood called ?
Ans: Plasma
Explanation: Plasma is the straw-colored liquid portion of blood. It transports nutrients, hormones, gases, and waste. It also maintains pH balance and helps in clotting.
Q. What is the hardest natural substance on Earth ?
Ans: Diamond
Explanation: Diamond is extremely hard because its carbon atoms are tightly bonded in a strong crystal structure. It is used in jewelry and for cutting tough materials.
Q. What do plants release during photosynthesis ?
Ans: Oxygen
Explanation: In photosynthesis, plants use sunlight to make food from carbon dioxide and water. Oxygen is released as a by-product, essential for the survival of most living beings.
Q. Which part of the brain controls basic bodily functions like breathing and heartbeat ?
Ans: Medulla oblongata
Explanation: The medulla oblongata controls involuntary functions such as breathing, heartbeat, swallowing, and blood pressure. It is essential for survival and works automatically.
Q. Which organ filters and purifies blood ?
Ans: Kidneys
Explanation: Kidneys remove waste, regulate water and mineral balance, and produce urine. They help maintain blood pressure and keep the body’s internal environment stable.
Q. What type of energy is stored in a stretched rubber band ?
Ans: Potential energy
Explanation: A stretched rubber band stores elastic potential energy. When released, this energy converts into kinetic energy, causing the band to snap back quickly.
Q. What unit is used to measure frequency in physics ?
Ans: Hertz (Hz)
Explanation: Frequency is measured in Hertz, meaning cycles per second. It tells how many times a wave—like sound or electromagnetic waves—repeats in one second.
General Science MCQ practice with Answers set-1
Q. What is the normal human body temperature ?
Ans: 37°C
Explanation: A healthy human body maintains an internal temperature close to 37°C. This temperature allows enzymes and metabolic processes to function properly and supports overall body homeostasis.
Q. The ozone layer is located about how many kilometers above Earth ?
Ans: About 50 km
Explanation: The ozone layer lies in the stratosphere, roughly 10–50 km above Earth. Its maximum concentration is around 50 km, where it absorbs harmful ultraviolet rays from the Sun.
Q. What type of radiation does the ozone layer absorb ?
Ans: Ultraviolet (UV) rays
Explanation: The ozone layer absorbs most dangerous UV-B and UV-C radiation from the Sun, preventing skin cancer, eye damage, and harm to plants and animals.
Q. Where is petroleum commonly found ?
Ans: Deep under the Earth’s surface
Explanation: Petroleum forms over millions of years from organic remains. It collects in underground sedimentary rock structures called reservoirs and is extracted through drilling.
Q. Which metal is usually found in free state in nature ?
Ans: Gold
Explanation: Gold is chemically unreactive, so it doesn’t easily combine with other elements. This allows it to be found naturally as pure nuggets or grains.
Q. What is the chemical name of baking soda ?
Ans: Sodium bicarbonate
Explanation: Sodium bicarbonate (NaHCO₃) is a white alkaline powder used in cooking. When heated or mixed with acid, it releases carbon dioxide, helping dough to rise.
Q. Rickets is caused by a deficiency of which vitamin ?
Ans: Vitamin D
Explanation: Vitamin D helps the body absorb calcium for strong bones. Its deficiency weakens bones in children, causing rickets, bone pain, and deformities.
Q. Which alcohol is produced in wine fermentation ?
Ans: Ethanol
Explanation: During fermentation, yeast converts sugars in grapes into ethanol and carbon dioxide. This chemical process gives wine its alcohol content.
Q. Milk protein is mainly made of what ?
Ans: Casein
Explanation: Casein makes up about 80% of milk protein. It supplies essential amino acids, helps in muscle growth, and gives milk its white color and thick texture.
Q. Which gas is called “laughing gas”?
Ans: Nitrous oxide (N₂O)
Explanation: Nitrous oxide produces a mild anesthetic effect and causes temporary euphoria and laughter. It is used in dental procedures for pain relief.
Q. Who developed the principle of inertia ?
Ans: Galileo
Explanation: Galileo first described inertia—the tendency of objects to stay at rest or continue motion unless acted upon by an external force. Newton later expanded this idea.
Q. Rice cultivation typically requires what soil condition ?
Ans: Water-logging
Explanation: Rice grows best in flooded fields (paddy fields). Water-logging prevents weeds, maintains soil temperature, and supports rice plant growth.
Q. Who discovered Vitamin C ?
Ans: Albert Szent-Györgyi
Explanation: Albert Szent-Györgyi isolated Vitamin C in 1928, showing its role in preventing scurvy and supporting immune function, healing, and antioxidant activity.
Q. What is the purest form of iron ?
Ans: Wrought iron
Explanation: Wrought iron contains very little carbon, making it the purest commercial form of iron. It is tough, malleable, and resistant to corrosion.
Q. Name the NASA rover that landed on Mars in 2012.
Ans: Curiosity
Explanation: The Curiosity rover landed on Mars in 2012 to study the planet’s climate, geology, and potential for past life. It continues to send valuable data.
Q. What is Earth's outermost layer called ?
Ans: The crust
Explanation: The crust is the thin, solid outer layer of Earth. It includes continents and ocean floors and is made of various rocks and minerals.
Q. What causes earthquakes ?
Ans: Movement of tectonic plates
Explanation: Earthquakes occur when tectonic plates shift suddenly at fault lines. This movement releases energy as seismic waves that shake the ground.
Q. What was the ancient supercontinent called ?
Ans: Pangaea
Explanation: Pangaea existed about 300 million years ago. It later split into separate continents due to tectonic plate movement.
Q. What is the continuous movement of water on Earth called ?
Ans: The water cycle
Explanation: The water cycle includes evaporation, condensation, precipitation, and runoff. It maintains Earth’s water balance and supports life.
Q. Rocks formed from molten lava are called ?
Ans: Igneous rocks
Explanation: Igneous rocks form when molten magma or lava cools and solidifies. Examples include basalt and granite.
Q. What is heat transfer through fluid movement called ?
Ans: Convection
Explanation: Convection occurs when warm fluid rises and cool fluid sinks, creating a circulation pattern that transfers heat in liquids and gases.
Q. What does a supernova involve ?
Ans: A star exploding
Explanation: A supernova is a massive explosion of a dying star. It releases enormous energy and spreads elements into space.
Q. What is Saturn’s largest moon ?
Ans: Titan
Explanation: Titan is Saturn’s largest moon and has a thick atmosphere. It contains lakes and rivers of liquid methane and ethane.
Q. What do we call a celestial object made of ice, dust, and rock ?
Ans: Comet
Explanation: Comets orbit the Sun and develop bright tails when solar heat vaporizes their ice. They come from the Kuiper Belt and Oort Cloud.
Q. What are planets outside our solar system called ?
Ans: Exoplanets
Explanation: Exoplanets orbit stars other than the Sun. Thousands have been discovered, some possibly capable of supporting life.
Q. How is the Sun’s energy generated ?
Ans: Nuclear fusion
Explanation: In nuclear fusion, hydrogen atoms combine to form helium, releasing massive energy. This powers the Sun’s heat and light.
Q. SO₂ and NOx contribute to which environmental issue ?
Answer: Air pollution (acid rain)
Explanation: Sulfur dioxide and nitrogen oxides react with atmospheric moisture to produce acid rain, damaging soil, water, plants, and buildings.
Q. What is Earth's largest source of freshwater ?
Ans: Glaciers and ice caps
Explanation: About 68% of Earth’s freshwater is locked in glaciers and ice caps, mainly in Antarctica and Greenland.
Q. What principle states energy cannot be created or destroyed ?
Ans: Law of conservation of energy
Explanation: This law states that energy only changes forms but the total amount remains constant in a closed system.
Q. What is the chemical formula for glucose ?
Ans: C₆H₁₂O₆
Explanation: Glucose is a simple sugar providing energy for living organisms. Its formula shows it contains six carbon, twelve hydrogen, and six oxygen atoms.