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Class 9–10 General Knowledge: Science practice questions

Practise science for Classes 9 and 10. Try the 10-question quiz below and see each answer explained straight away, then read all 22 questions with answers underneath. Free, no sign-up.

All science questions with answers

1. What is the SI unit of electric current?

   1. A. Ohm
   2. B. Ampere ✓
   3. C. Volt
   4. D. Watt

   Answer: Ampere. Current is measured in amperes.

2. What is the atomic number of carbon?

   1. A. 8
   2. B. 6 ✓
   3. C. 4
   4. D. 12

   Answer: 6. A carbon atom has 6 protons.

3. Which hormone controls the level of sugar in the blood?

   1. A. Adrenaline
   2. B. Insulin ✓
   3. C. Thyroxine
   4. D. Oestrogen

   Answer: Insulin. Insulin from the pancreas lowers blood sugar.

4. Rusting of iron needs oxygen and which other thing?

   1. A. Nitrogen
   2. B. Light
   3. C. Carbon dioxide
   4. D. Water ✓

   Answer: Water. Iron rusts when it is in contact with both oxygen and water.

5. What is common salt chemically?

   1. A. Calcium chloride
   2. B. Sodium carbonate
   3. C. Sodium chloride ✓
   4. D. Potassium chloride

   Answer: Sodium chloride. Common salt is NaCl, sodium chloride.

6. Which type of mirror is used as a rear-view mirror in vehicles?

   1. A. Concave mirror
   2. B. Convex mirror ✓
   3. C. Cylindrical mirror
   4. D. Plane mirror

   Answer: Convex mirror. A convex mirror gives a wider field of view.

7. Roughly what is the speed of light in a vacuum?

   1. A. 3 × 10⁵ m/s
   2. B. 3 × 10⁶ m/s
   3. C. 3 × 10⁸ m/s ✓
   4. D. 3 × 10¹⁰ m/s

   Answer: 3 × 10⁸ m/s. Light travels about 300,000 km every second.

8. Which acid is found in lemons?

   1. A. Hydrochloric acid
   2. B. Acetic acid
   3. C. Citric acid ✓
   4. D. Lactic acid

   Answer: Citric acid. Lemons and other citrus fruits contain citric acid.

9. Which gas is released when zinc reacts with dilute hydrochloric acid?

   1. A. Carbon dioxide
   2. B. Chlorine
   3. C. Oxygen
   4. D. Hydrogen ✓

   Answer: Hydrogen. Metal + acid gives a salt and hydrogen gas.

10. Which organelle in a plant cell carries out photosynthesis?

    1. A. Chloroplast ✓
    2. B. Nucleus
    3. C. Mitochondria
    4. D. Golgi body

    Answer: Chloroplast. Chloroplasts contain chlorophyll, which traps sunlight.

11. What is the SI unit of work and energy?

    1. A. Joule ✓
    2. B. Pascal
    3. C. Newton
    4. D. Watt

    Answer: Joule. Work and energy are measured in joules.

12. Which layer of the atmosphere protects us from harmful ultraviolet rays?

    1. A. Ozone layer ✓
    2. B. Ionosphere
    3. C. Troposphere
    4. D. Exosphere

    Answer: Ozone layer. The ozone layer absorbs most of the Sun's ultraviolet radiation.

13. What is the SI unit of resistance?

    1. A. Ampere
    2. B. Ohm ✓
    3. C. Joule
    4. D. Volt

    Answer: Ohm. Resistance is measured in ohms.

14. What is the pH of a neutral solution such as pure water?

    1. A. 8
    2. B. 14
    3. C. 1
    4. D. 7 ✓

    Answer: 7. Below 7 is acidic, above 7 is basic and 7 is neutral.

15. Which instrument measures atmospheric pressure?

    1. A. Barometer ✓
    2. B. Thermometer
    3. C. Hygrometer
    4. D. Anemometer

    Answer: Barometer. A barometer measures air pressure.

16. Which law says every action has an equal and opposite reaction?

    1. A. Newton's second law
    2. B. Newton's first law
    3. C. Newton's third law ✓
    4. D. Ohm's law

    Answer: Newton's third law. That is Newton's third law of motion.

17. Which part of the cell is called its powerhouse?

    1. A. Mitochondria ✓
    2. B. Vacuole
    3. C. Ribosome
    4. D. Nucleus

    Answer: Mitochondria. Mitochondria release energy from food.

18. Which blood group is known as the universal donor?

    1. A. AB positive
    2. B. O negative ✓
    3. C. B negative
    4. D. A positive

    Answer: O negative. O negative red cells can be given to almost anyone.

19. Which lens is used to correct short-sightedness (myopia)?

    1. A. Concave lens ✓
    2. B. Bifocal lens
    3. C. Convex lens
    4. D. Cylindrical lens

    Answer: Concave lens. A concave lens spreads light so that the image falls on the retina.

20. Which particle in an atom carries a negative charge?

    1. A. Electron ✓
    2. B. Proton
    3. C. Neutron
    4. D. Nucleus

    Answer: Electron. Electrons are negative, protons positive and neutrons neutral.

21. Which gas is commonly used in fire extinguishers?

    1. A. Hydrogen
    2. B. Oxygen
    3. C. Carbon dioxide ✓
    4. D. Methane

    Answer: Carbon dioxide. Carbon dioxide does not burn and smothers the flame.

22. Which process turns a liquid into vapour at any temperature below its boiling point?

    1. A. Condensation
    2. B. Freezing
    3. C. Evaporation ✓
    4. D. Sublimation

    Answer: Evaporation. Evaporation happens at the surface of a liquid below its boiling point.

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