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Which of the following is not likely to cause Tsunami? (a) A major nuclear explosion undersea (b) Earthquake (c) Volcanic eruption (d) Lightning

Answer: (d) Lightning Tsunamis are caused by a disturbance deep under the surface of the water. Lightening will not harm the sea, but... View Article

Which of the following metals is used in electroplating to make objects appear shining? (a) iron (b) copper (c) chromium (d) aluminium

Answer: (c) chromium Electroplating is the process of aligning another metal onto metal. This is accomplished using an electroplating apparatus... View Article

Which of the following solutions will not make the bulb in Fig glow? (a) sodium chlorides (b) copper sulphate (c) silver nitrate (d) sugar solution in distilled water

Answer: (d) sugar solution in distilled water In diluted water, sugar solution does not produce free ions. As a result, it is regarded as a poor... View Article

Which of the following statements are correct? (i) Sound is produced by vibrations. (ii) Sound requires a medium for propagation. (iii) Light and sound both require a medium for propagation. (iv) Sound travels slower than light. (a) i & ii only (b) i, ii & iii only (c) ii, iii & iv only (d) i, ii & iv only

Answer:(d) i, ii & iv only Although light may travel in a vacuum, only sound requires a medium to travel. Sound needs a material medium for... View Article

Which of the following statements is correct regarding rods and cones in the human eye? (a) Cones are sensitive to dim light. (b) Cones are sensitive to bright light. (c) Rods are sensitive to bright light. (d) Rods can sense colour.

Answer: (b) Cones are sensitive to bright light. Cones sense colour because they are sensitive to bright light, whereas rods are sensitive to low... View Article

Which of the following statements is correct? (a) All metals are ductile. (b) All non-metals are ductile. (c) Generally, metals are ductile. (d) Some non-metals are ductile.

Answer: (c) Generally, metals are ductile. Ductility is a quality that allows a substance to be pulled into thin wires. Most metals are ductile,... View Article

Which of the following statements is incorrect? (a) Friction acts on a ball rolling along the ground. (b) Friction acts on a boat moving on water. (c) Friction acts on a bicycle moving on a smooth road. (d) Friction does not act on a ball moving through air.

Answer: (d) Friction does not act on a ball moving through air. Friction acts on a body moving in the air as fluid friction Friction is caused... View Article

Which of the following statements is not correct? (i) Forests protect the soil from erosion. (ii) Plants and animals in a forest are not dependent on one another. (iii) Forests influence the climate and water cycle. (iv) Soil helps forests to grow and regenerate.

Answer: (ii) Plants and animals in a forest are not dependent on one another. This is due to the fact that plants and animals rely on one another... View Article

Which of the following statements is not true about an atom? (a) Atoms are not able to exist independently (b) Atoms are the basic units from which molecules and ions are formed (c) Atoms are always neutral in nature d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch

Answer: (a) Atoms are not able to exist independently It is not true that atoms cannot exist independently. Atoms of most elements cannot exist... View Article

Which of the following would weigh the highest? (a) 0.2 mole of sucrose (C¹²H²² O¹¹) (b) 2 moles of CO² (c) 2 moles of CaCO³ (d) 10 moles of H²O

Answer: (c) 2 moles of CaCO3 The molecular mass of C12H22O11 Carbon = 12 Hydrogen = 1 Oxygen = 16 C12H22O11 = 12(12) + 22(1) + 11(16) gm... View Article

Which of the statements given below is correct? (i) In winter the winds flow from the land to the ocean. (ii) In summer the winds flow from the land towards the ocean. (iii) A cyclone is formed by a very high-pressure system with very high-speed winds revolving around it. (iv) The coastline of India is not vulnerable to cyclones.

Answer: (i) In winter, the winds flow from the land to the ocean. The wind is an air movement having both direction and speed. It is made up of... View Article

Which of the two changes frequently, weather or climate?

Answer: Weather changes frequently but not climate. A climate is average weather in a given area over a period of time. The weather, on the... View Article

Which one of the following forces is a contact force? (a) force of gravity (b) force of friction (c) magnetic force (d) electrostatic force

Answer: (b) force of friction Contact force is a force that is applied by objects in contact with each other. The contact force acts on a point... View Article

Which one of the following places is unlikely to be affected by a cyclone? (i) Chennai (ii) Mangaluru (Mangalore) (iii) Amritsar (iv) Puri

Answer: (iii) Amritsar Cyclone is defined as the mass of air that rotates around the centre of low pressure on a large scale. Cyclone is... View Article

Which one of the following solutions will not conduct electricity? (a) lemon juice (b) vinegar (c) tap water (d) vegetable oil

Answer: (d) vegetable oil Because vegetable oil is lacking ions, it is unable to conduct electricity. Materials that have good mobility of... View Article

Which part of the eye gets affected if someone is suffering from cataract? How is it treated?

Answer: If a person is suffering from a cataract their eye lens will be cloudy. Cataracts can be treated by replacing the opaque lens with an... View Article

While sieving grains, small pieces fall down. Which force pulls them down?

Answer: Force of gravity is responsible for the grains to fall down. According to Newton’s universal law of gravitation, the force of... View Article

While travelling on a rickshaw, you might have experienced that if the seat cover is very smooth, you tend to slip when brakes are applied suddenly. Explain.

Answer: The friction between the seat and our body is minimized if the seat cover is very smooth. As a result, when the brakes are applied in a... View Article

Why does the moon change its shape daily?

Answer: Because the moon revolves around the earth, its form varies on a daily basis, and we only see the part of the moon from which the sun's... View Article

Why is a layer of zinc-coated over iron?

Answer: Rust is developed when iron reacts with ambient air. Zinc is coated with iron to keep it from rusting. A rust-prevention technique is... View Article

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