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Q1. The amount of space an object occupies is called its:
Volume is the total space that an object takes up. It can be measured in litres, millilitres or cubic centimetres.
Q2. The volume of a liquid is usually measured in:
Liquids like water and milk are measured in litres and millilitres. A measuring cylinder or a jug is used to measure liquid volume.
Q3. The volume of a solid object can be found by:
For regular solids like a cuboid, volume is calculated by multiplying length, breadth and height. For irregular solids, water displacement method is used.
Q4. The amount of matter contained in an object is called its:
Mass is the amount of matter or “stuff” inside an object. It does not change even if the object moves to another place.
Q5. The force with which the Earth pulls an object towards itself is called its:
Weight is the force of gravity acting on an object. It depends on the mass of the object and the gravitational pull of the Earth.
Q6. Weight is measured using a:
A spring balance measures the weight of an object by stretching the spring. It shows the force of gravity on the object.
Q7. Mass is measured using a:
A beam balance compares the mass of an object with standard weights. It gives the mass in kilograms or grams.
Q8. The unit of weight is:
Weight is a force, so it is measured in Newtons. A Newton is the force needed to move a 100-gram object.
Q9. The unit of mass is:
Mass is measured in kilograms or grams. One kilogram is the standard unit of mass.
Q10. The density of an object is its:
Density tells us how tightly packed the matter is in an object. It is found by dividing mass by volume.
Q11. If two objects have the same volume, the one with more mass will have:
If the mass is more in the same volume, the object is denser. This means the matter is packed more tightly.
Q12. The density of water is about:
Water has a density of 1 gram per cubic centimetre. This is used as a standard to compare other objects.
Q13. An object that has a density less than water will:
If an object is less dense than water, it will float. This is because it weighs less than the water it displaces.
Q14. An object that has a density more than water will:
If an object is denser than water, it sinks. This is because it weighs more than the water it displaces.
Q15. An object that floats on water experiences an upward force called:
Buoyant force is the upward push that water gives to an object. This force helps objects to float.
Q16. The upward force exerted by a liquid on an object is called:
When an object is put in water, the water pushes it up. This upward push is called buoyant force or upthrust.
Q17. Buoyant force is also called:
Buoyant force is called upthrust because it pushes objects upward in liquids. This is what makes heavy ships float.
Q18. A boat floats on water because:
The water pushes the boat up with a force called buoyant force. If this force is more than the boat’s weight, the boat floats.
Q19. A piece of iron sinks in water because:
Iron is denser than water, so it weighs more than the water it displaces. This makes it sink.
Q20. A ship made of iron floats because:
A ship is hollow inside and takes up a large volume. This makes it displace enough water to create buoyant force that holds it up.
Q21. An object will float in a liquid if:
Less dense objects float because they are lighter than the liquid they push aside. The buoyant force lifts them up.
Q22. An object will sink in a liquid if:
Denser objects sink because they are heavier than the liquid they push aside. Gravity pulls them down more than the buoyant force pushes them up.
Q23. A piece of wood floats on water because:
Wood is less dense than water, so it floats. The buoyant force of the water is stronger than the weight of the wood.
Q24. A stone sinks in water because:
A stone is denser than water, so it sinks. The weight of the stone is greater than the buoyant force of water.
Q25. A plastic ball floats in water. If the same ball is pushed down, it will:
The buoyant force of water pushes the ball back up. Because the ball is less dense than water, it rises to the surface.
Q26. The buoyant force acts in the direction:
Buoyant force always acts in the upward direction. It pushes objects against gravity, helping them float.
Q27. The force of gravity acts in the direction:
Gravity pulls everything towards the centre of the Earth. It acts in the downward direction.
Q28. When an object floats, the buoyant force is:
A floating object is balanced when the buoyant force is equal to its weight. This balance keeps it floating without sinking or rising.
Q29. When an object sinks, the buoyant force is:
An object sinks when its weight is greater than the buoyant force. Gravity pulls it down more than the water pushes it up.
Q30. The volume of an irregular solid can be measured by:
When an irregular solid is put in water, it pushes water out of the way. The rise in water level shows the volume of the solid.
Q31. A measuring cylinder is used to measure:
A measuring cylinder has markings that show the volume of liquid in millilitres. It is used to measure how much liquid there is.
Q32. A stone has a density of 2.5 g/cm³. It will:
The stone is denser than water (which has density 1 g/cm³). Objects with density more than water will sink.
Q33. A piece of cork floats on water. Its density is:
Cork floats because its density is less than water’s density of 1 g/cm³. It is lighter than the water it displaces.
Q34. The density of an object does not depend on its:
Density is a property of the material itself. Changing the size or shape does not change the density of the object.
Q35. A kilogram of iron and a kilogram of cotton have:
Both have the same mass of 1 kilogram. Iron has a smaller volume because it is denser than cotton.
Q36. A ship floats lower in fresh water than in sea water because:
Sea water is denser because it has salt dissolved in it. The buoyant force is greater in sea water, so a ship floats higher.
Q37. A submarine can float and sink because:
A submarine takes in water to become heavier and sink. It pumps out water to become lighter and float back up.
Q38. A hot air balloon rises because:
Hot air inside the balloon is less dense than the cooler air outside. This makes the balloon lighter and it rises.
Q39. An iceberg floats in the ocean because:
Ice is less dense than liquid water, so it floats. This is why icebergs are seen floating in the ocean.
Q40. A helium-filled balloon rises because:
Helium gas is lighter than air, so the balloon rises. The buoyant force of air pushes the balloon up.
Q41. The mass of an object on the Moon is:
Mass is the amount of matter in an object and never changes. Even on the Moon, the mass stays the same.
Q42. The weight of an object on the Moon is:
Weight depends on gravity, which is weaker on the Moon. So, an object weighs less on the Moon.
Q43. A wooden block floats in water. If we push it under water and release, it will:
The buoyant force pushes the wooden block upwards. Since it is less dense than water, it returns to the surface.
Q44. The upthrust on an object in water depends on:
The upthrust or buoyant force depends on how much water the object pushes aside. More displaced water means more upthrust.
Q45. A cube of side 2 cm has a volume of:
Volume of a cube is side × side × side = 2 × 2 × 2 = 8 cm³. This is the space it occupies.
Q46. The density of an object is calculated by:
Density tells us how much mass is in a given volume. It is found by dividing mass by volume.
Q47. An object weighing 300 grams has a volume of 100 cm³. Its density is:
Density = Mass ÷ Volume = 300 ÷ 100 = 3 g/cm³. This object is denser than water.
Q48. An object weighing 50 grams has a volume of 100 cm³. Its density is:
Density = Mass ÷ Volume = 50 ÷ 100 = 0.5 g/cm³. This object is less dense than water and will float.
Q49. The formula for calculating density is:
Density (D) = Mass (M) divided by Volume (V). This formula helps us find the density of any object.
Q50. A rectangular block has a volume of 200 cm³ and a mass of 600 g. Its density is:
Density = Mass ÷ Volume = 600 ÷ 200 = 3 g/cm³. This is how much mass is packed into each cubic centimetre.
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Q51. When an object is fully submerged in water, the water level rises. This rise in level is equal to the:
The water level rises by the amount of water the object displaces. This displaced water volume is equal to the object’s volume.
Q52. Fishes have a special organ called a swim bladder that helps them:
The swim bladder fills with gas to make the fish lighter and helps it float. It empties to make the fish heavier and sink.
Q53. The buoyant force of a liquid depends on the:
Denser liquids exert more buoyant force. This is why objects float more easily in salt water than in fresh water.
Q54. A piece of plastic floats in water but sinks in alcohol because:
Alcohol has a lower density than water. If the plastic is denser than alcohol but less dense than water, it will sink in alcohol and float in water.
Q55. A steel needle sinks in water, but a steel ship floats because:
A ship is hollow inside and takes up a large volume. This displaces enough water to create huge buoyant force that holds it up.
Q56. An object will have less upthrust in:
Fresh water is less dense than sea water, so it exerts less buoyant force. Objects feel lighter in sea water.
Q57. The upthrust is maximum when an object is:
More water is displaced when the object is fully submerged. A denser liquid also gives more upthrust.
Q58. A brick sinks in water but floats in mercury because:
Mercury is a very dense liquid. The buoyant force of mercury is so strong that even a brick can float in it.
Q59. To find the volume of a stone using a measuring cylinder, we:
The stone pushes water up when placed in the cylinder. The rise in water level shows the volume of the stone.
Q60. A floating object displaces water equal to its:
According to Archimedes’ principle, a floating object displaces water whose weight is equal to its own weight. This keeps it afloat.