1. 1. Which metal is used in making coins ?
Copper is widely used for making coins because it is strong, corrosion-resistant, and easy to shape. Modern coins often use copper alloys like bronze or cupronickel for durability and shine.
2. Which instrument is used to measure electric potential difference ?
A voltmeter measures the electric potential difference (voltage) between two points in a circuit. It is connected in parallel and shows how much energy per charge is transferred.
3. What is dry ice ?
Dry ice is solid carbon dioxide, which changes directly from solid to gas (sublimation). It is used for cooling, fog effects, and preserving food since it leaves no liquid.
4. Which vitamin is produced in the body by sunlight ?
When skin is exposed to sunlight, ultraviolet rays help the body produce vitamin D, which is essential for bone strength, calcium absorption, and prevents rickets and osteoporosis.
5. Which blood group is known as universal donor ?
Blood group O is called the universal donor because its red blood cells lack A and B antigens, making it safe to donate to any other blood group without reaction.
6. Which device is used to measure temperature ?
A thermometer measures temperature using substances like mercury or alcohol that expand with heat. It is used in homes, laboratories, and hospitals to check body and environmental temperatures.
7. Which gas is essential for respiration ?
Oxygen is vital for respiration, the process where living organisms break down food molecules to release energy. It helps produce ATP, the main energy source in body cells.
8. Which planet is known as the “Morning Star” ?
Venus appears bright before sunrise and after sunset, so it’s called the Morning Star or Evening Star. It reflects sunlight strongly due to its thick cloudy atmosphere.
9. Which part of the cell controls all its activities ?
The nucleus is the control center of the cell. It contains DNA, which stores genetic information and directs cell growth, division, and protein synthesis.
10. What is the chemical formula of water ?
Water’s chemical formula H₂O means it has two hydrogen atoms and one oxygen atom. It’s essential for life processes, temperature regulation, and chemical reactions in all organisms.
11. Which gas is essential for photosynthesis ?
Plants use carbon dioxide during photosynthesis to produce glucose and oxygen. With the help of sunlight and chlorophyll, CO₂ combines with water to make food for the plant.
12. What is the SI unit of force ?
The SI unit of force is the Newton (N), named after Sir Isaac Newton. One Newton equals the force required to accelerate a 1 kg mass by 1 m/s².
13. Which part of the human body controls balance ?
The cerebellum, located at the back of the brain, helps maintain body balance, coordination, and posture. It ensures smooth and accurate movements during walking, running, or any activity.
14. Which non-metal is a good conductor of electricity ?
Graphite, a form of carbon, conducts electricity because its free electrons can move between layers. It is used in electrodes and pencil leads due to its unique structure.
15. Which planet has the largest number of moons ?
Saturn has the largest number of moons, over 80 confirmed, including Titan, the biggest. Its strong gravity captures many natural satellites, making it a fascinating planet in our solar system
16. Which acid is present in lemon ?
Lemons contain citric acid, which gives them a sour taste. This weak organic acid is also found in oranges and helps in digestion and vitamin C absorption in the body.
17. What is the boiling point of water ?
The boiling point of water is 100°C (212°F) at normal atmospheric pressure. At this temperature, water changes from liquid to vapor, forming steam through boiling.
18. Which organ in the human body stores bile
The gall bladder stores bile produced by the liver. Bile helps in digesting fats in the small intestine by breaking large fat molecules into smaller droplets.
19. Which planet is closest to the Sun ?
Mercury is the closest planet to the Sun and completes its orbit in just 88 Earth days. It has extreme temperatures and no atmosphere to retain heat.
20. Which metal is used in making electric wires ?
Copper is widely used in electric wires because it is a good conductor of electricity, ductile, and resists corrosion, ensuring smooth and efficient current flow in circuits.
21. What is the chemical symbol of sodium ?
The chemical symbol for sodium is Na, derived from its Latin name ‘Natrium’. Sodium is a soft, reactive metal found in common salt (NaCl) and many compounds.
22. Which organ of the human body purifies blood ?
The kidneys purify blood by filtering waste and excess water, forming urine. They maintain the body’s chemical balance and help control blood pressure and fluid levels.
23. Which planet is known as the Blue Planet ?
Earth is called the Blue Planet because about 71% of its surface is covered with water. The oceans reflect sunlight, giving Earth its beautiful blue appearance from space.
24. Which gas is used in fire extinguishers ?
Carbon dioxide (CO₂) is used in fire extinguishers because it does not support combustion and displaces oxygen, suffocating flames and quickly putting out fires safely.
25. What is the hardest natural substance on Earth ?
Diamond is the hardest natural substance, made of pure carbon atoms arranged in a strong crystal structure. It is used in cutting tools and jewelry due to its extreme hardness.
26. Which part of the plant conducts water ?
Xylem carries water and minerals from roots to other parts of the plant. It forms hollow tubes that help maintain the plant’s water balance and strength.
27. Which gas do humans exhale during respiration ?
During respiration, humans inhale oxygen and exhale carbon dioxide. CO₂ is produced as a waste product when cells use oxygen to release energy from food.
28. Which of the following is a renewable source of energy ?
Wind energy is renewable because it never runs out. Wind turbines convert kinetic energy of air into electricity without causing pollution or greenhouse gas emissions.
29. What is the normal human body temperature ?
The average human body temperature is 98.6°F (37°C), necessary for enzyme function and metabolic processes. Slight changes can indicate fever or illness.
30. Which instrument measures atmospheric pressure ?
A barometer measures air (atmospheric) pressure, helping predict weather changes. Falling pressure usually means rain, while rising pressure signals clear weather.
31. Which planet is known as the Red Planet ?
Mars is called the Red Planet due to iron oxide (rust) on its surface, giving it a reddish appearance visible even with the naked eye.
32. Which vitamin helps in blood clotting ?
Vitamin K helps in blood clotting by producing proteins that prevent excessive bleeding. It is found in green leafy vegetables and produced by gut bacteria.
33. Which gas is used for breathing by deep-sea divers ?
Deep-sea divers use a mixture of oxygen and helium, not nitrogen, to avoid nitrogen narcosis. Helium is safe and light, making breathing easier under high pressure.
34. Which metal is liquid at room temperature ?
Mercury is the only metal that remains liquid at room temperature. It expands evenly with heat and is used in thermometers and barometers.
35. The unit of electric current is –
The ampere (A) is the SI unit of electric current, measuring the flow of charge per second through a conductor. Named after André-Marie Ampère, a French physicist
36. Which organ purifies blood in humans ?
Kidneys filter wastes and toxins from the blood, forming urine. They also balance water and salts, maintaining proper body chemistry and fluid levels.
37. Which metal is used in thermometers ?
Mercury expands uniformly with temperature changes, making it ideal for thermometers. It is visible, shiny, and conducts heat efficiently.
38. The phenomenon of splitting white light into colors is called –
Dispersion occurs when white light splits into seven colors (VIBGYOR) on passing through a prism because each color bends at a different angle.
39. Which planet is called the Red Planet ?
Mars gets its red color from iron oxide on its surface. It’s the fourth planet from the Sun and resembles Earth in many geological features.
40. Which gas is used in fire extinguishers ?
Carbon dioxide extinguishes fires by cutting off oxygen supply and cooling flames. It’s commonly used for electrical and chemical fires.
41. What is the main component of natural gas ?
Methane (CH₄) is the main component of natural gas. It is colorless, odorless, and burns easily, producing energy for cooking, heating, and electricity.
42. Which disease is caused by mosquito bite ?
Malaria is transmitted by the female Anopheles mosquito carrying Plasmodium parasites. It causes fever, chills, and weakness, mostly in tropical regions.
43. What is the normal body temperature of humans ?
Human body temperature averages 98.6°F (37°C). It keeps enzymes active for vital functions. Fever indicates the body fighting infection.
44. What is the chemical name of common salt ?
Common salt (NaCl) is formed by sodium and chlorine. It’s used in food, preservation, and industries, and helps maintain body fluid balance.
45. Which gas do plants release during photosynthesis ?
During photosynthesis, plants use sunlight to make food from CO₂ and water, releasing oxygen — essential for all living beings.
46. Which instrument measures atmospheric pressure ?
A barometer measures air pressure. It helps forecast weather — lower pressure means rain, higher pressure means clear skies.
47. Which vitamin helps in blood clotting ?
Vitamin K assists in producing clotting proteins, preventing excessive bleeding. It is found in spinach, kale, and broccoli.
48. Which organ controls all functions of the body ?
The brain is the control center of the body, managing movement, memory, and coordination through the nervous system.
49. Which part of the plant is called the “Kitchen of the plant” ?
The leaf is called the “Kitchen of the plant” because it performs photosynthesis, producing food using sunlight, CO₂, and water.
50. What is used in making safety matches ?
Phosphorus in match heads reacts with chemicals on the box surface to ignite flame when struck. It ensures controlled ignition and safety.