Selina solutions for Concise Physics [English] Class 8 ICSE chapter 2 - Physical Quantities and Measurement [Latest edition]

Equal volumes of the two different substances have equal masses.

The density of a piece of brass will change by changing its size or shape.

The density of a liquid decreases with increase in its temperature.

Relative density of water is 1.0.

Relative density of a substance is expressed in g cm-3.

When a body is immersed in a liquid, the buoyant force experienced by the body is equal to the volume of the liquid displaced by it.

A body experiences the same buoyant force while floating in water or alcohol.

A body experiences the same buoyant force when it floats or sinks in water.

A body floats in a liquid when its weight becomes equal to the weight of the liquid displaced by its submerged part. 

A body while floating sinks deeper in a liquid of low density than in a liquid of high density.

1 kg is the mass of ............ml of water at 4°C.

Mass = density x .........

The S.I. unit of density is ..........

Density of water is .......Kg m^-3.

1 g cm^-3 = ......... Kg m^-3.

The density of a body which sinks in water is ......... than 1000 Kg m^-3.

A body sinks in a liquid A but floats in a liquid B. The density of liquid A is ....... than the density of liquid B.

A body X sinks in water, but a body Y floats on water. The density of the body X is ......... than the density of body Y.

The buoyant force experienced by a body when floating in saltwater is ....... to or same that of when floating in pure water.

The weight of a body floating in a liquid is ........

 Match the following :

The correct relation is

The relative density of alcohol is 0.8. Its density is

A block of wood of density 0.8 g cm-3 has a volume of 60 cm3. The mass of block is

The density of aluminium is 2.7 g cm-3 and that of brass 8.4 g cm’3. The correct statement is

A density bottle has a marking 25 ml on it. It means that:

The correct statement is

A piece of wood floats on water. The buoyant force on wood will be

The weight of a body is more than the buoyant force experienced by it, due to a liquid. The body will

Define the term Density of a substance.

Name the S.I. unit of density. How is it related to g Cm^-3?

The density of brass is 8.4 g cm-3. What do you mean by this statement?

Arrange the following substances in order of their increasing density:
Iron, Cork, Brass, Water, Mercury.

How does the density of a liquid (or gas) vary with temperature?

A given quantity of a liquid is heated. Which of the following quantity will vary and how?
(a) mass, (b) volume and (c) density

Describe an experiment to determine the density of the material of a coin.

Describe an experiment to determine the density of a liquid.

What is a density bottle? How is it used to find the density of a liquid?

Define the term relative density of a substance.

What is the unit of relative density?

Distinguish between density and relative density.

Explain the meaning of the statement

‘Relative density of aluminium is 2.7’.

How does the density of a body and that of a liquid determine whether the body will float or sink into that liquid?

A cork piece floats on water surface while an iron nail sinks in it. Explain the reason.

Which of the following will sink or float on water? (Density of water = 1 g Cm^-3)
(a) body A having density of 500 kg m^-3

Which of the following will sink or float on water? (Density of water = 1 g Cm^-3) body B having density 2520 kg m^-3

Which of the following will sink or float on water? (Density of water = 1 g Cm^-3)

 body C having density 1100 kg m^-3

Which of the following will sink or float on water? (Density of water = 1 g Cm^-3)

body D having density 0.85 g m^-3

What is the law of floatation?

The density of water is 1.0 g Cm^-3. The density of iron is 7.8 × 10″3 g Cm^-3. The density of mercury is 13.6 g Cm^-3.
Ans the following:
Will a piece of iron float or sink in water?

The density of water is 1.0 g Cm^-3. The density of iron is 7.8 × 10″3 g Cm^-3. The density of mercury is 13.6 g Cm^-3.
Answer the following:
Will a piece of iron float or sink in mercury?

The diagram given below show a body floating in three different liquids. A, B and C at different levels.
(a) In which liquid does the body experience the greatest buoyant force?
(b) Which liquid has the least density?
(c) Which liquid has the highest density?

For a floating body, how is its weight related to the buoyant force?

Why does a piece of ice float on water?

Explain why an iron needle sinks in water, but a ship made of iron floats on water.

It is easier to swim in sea water than in river water. Explain the reason.

Icebergs floating on sea water are dangerous for ships. Explain the reason.

Explain why it is easier to lift a stone under water than in air.

What is a submarine? How can it be made to dive in water and come to the surface of water?

A balloon filled with hydrogen rises in air. Explain the reason.

The density of air is 1.28 g/Iitre. Express it in g cm^-3  

The density of air is 1.28 g/Iitre. Express it in kg m^-3 

The dimensions of a hall are 10 m × 7 m × 5 m. If the density of air is 1.11 kg m^-3, find the mass of air in the hall.

The density of aluminium is 2.7 g cm³. Express it in kg m⁻³.

The density of alcohol is 600 kg m^-3. Express it in g Cm^-3.

A piece of zinc of mass 438.6 g has a volume of 86 cm³. Calculate the density of zinc.

A piece of wood of mass 150 g has a volume of 200 Cm³. Find the density of wood in C.GS. unit and S.I. unit.

Calculate the volume of wood of mass 6000 kg if the density of wood is 0.8 g Cm^-3

Calculate the density of solid from the following data :
(a) Mass of solid = 72 g
(b) Initial volume of water in measuring cylinder = 24 ml
(c) Final volume of water when solid is completely immersed in water = 42 ml

The mass of an empty density bottle is 21.8 g when filled completely with water is 41.8 g and when filled completely with liquid it is 40.6 g. Find

1. the volume of density bottle.
2. the relative density of liquid.

From the following observations, calculate the density and relative density of a brine solution.

Mass of empty density bottle = 22 g

Mass of bottle + water = 50 g

Mass of bottle + brine solution = 54 g

The mass of an empty density bottle is 30 g, it is 75 g when filled completely with water and 65 g when filled completely with a liquid. Find volume of density bottle.

The mass of an empty density bottle is 30 g, it is 75 g when filled completely with water and 65 g when filled completely with a liquid. Find density of liquid.

The mass of an empty density bottle is 30 g, it is 75 g when filled completely with water and 65 g when filled completely with a liquid. Find relative density of liquid.