(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

What are the units density in (i) C.G.S. and (ii) S.I. system .

Express the relationship between the C.G.S. and S.I. units of density. 

'The density of iron is 7800 kg m^-3'. What do you understand by this statement?

Write the density of water at 4°C in S.I. unit .

Water is heated from 0°C to 10°C . How does the density of water change with temperature?

Complete the following sentence.

Density of water is .... ... kg m^-3.

A body weighs W gf in air and W₁ gf when it is completely immersed in water. Find: (i) Volume of the body, (ii) Upthrust on the body and (iii) Relative density of the material of the body. 

The density of water is : 

Calculate the mass of air in a room of dimensions 4.5 m × 3.5 m × 2.5 m if the density of air at N.T.P. is 1.3 kgm^-3 . 

A piece of iron weighs 44.5 gf in air. If the density of iron is 8.9 × 10³, find the weight of iron piece when immersed in water.

A jeweller claims that he makes ornaments of pure gold that has a relative density of 19.3. He sells a bangle weighing 25.25 gf to a person. The clever customer weighs the bangle when immersed in water and finds that it weighs 23.075 gf in water. With the help of suitable calculations, find out whether the ornament is made of pure gold or not.

[Hint : calculate R.D. of material of bangle which comes out to be 11.6].

How does the density ρ_s of a substance determine whether a solid piece of that substance will float or sink in a given liquid ρ_L? 

Explain why an iron nail floats on mercury, but it sinks in water.

Hint : Density of iron is less than that of mercury, but more than that of water. 

A body floats in a liquid with a part of it submerged inside the liquid. Is the weight of floating body greater than, equal to or less than the upthrust?

A man first swims in sea water and then in river water. (i) Compare the weights of sea water and river water displaced by him.

(ii) Where does he find it easier to swim and why? 

What can you say about the average density of a ship floating on water in relation to the density of water? 

A loaded cargo ship sails from sea water to river water. State and Explain your observations. 

Explain the following : 

An egg sinks in fresh water, but floats in a strong salt solution.

Explain the following : 

Toy balloons filled with hydrogen rise to the ceiling, but if they are filled with carbon dioxide, then they sink to the floor.