Explore topic-wise InterviewSolutions in .

Radius of the sphere = 2 cm

Volume of the sphere = \(\frac{4}{3}\)πr³ = \(\frac{4}{3}\,\times\frac{22}{7}\,\times2\,\times2\,\times2\) = 33.52 cm³

Mass of the sphere = 0.05 kg = 50 gm

Density of the sphere = Mass / Volume = 50 / 33.52 = 1.49 gm/cm³

Relative density = Density of the sphere / Density of water = \(\frac{1.49 \,gm/cm^3}{1\,gm/cm^3}\) = 1.49

a) Density of solid = Mass of solid / Volume of solid

= 500g/350 cm³ 

= 1.42 g/cm³

b) Relative density of solid = Density of solid / Density of water 

= (1.42g/cm³) / (1g/cm³) 

= 1.42

c) Relative density of solid is greater than the relative density of water. So, it will sink in water.

Density is defined as the mass per unit volume.

Density = mass / volume

Units : Unit for density is gm/cm³ (or) kg/m³.

Relative density is the ratio of density of an object to the density of water.

Relative density of an object = density of the object / density of water

Units : Relative density has no units.

• We know that a piece of iron sinks in water. 
• The relative density of iron is 8.5 which is many times more than water. 
• A ship that floats on water is made up of tonnes of iron. It is really wonderful. 
• According to the Archimedes principle of buoyancy, any object can float when its weight is equal to the weight of water displaced by it. 
• Hence ships are made with a larger surface area so that it displaces the water, whose weight is equal to the weight of loaded ship.
• It involves very sharp scientific calculations and a large engineering technology. 
• Really such type of technologies are highly appreciable and the scientists who formulates all these are also really great.

Density of  substance = mass of substance / Volume of substance

 = -(50/20) = - 2.5 g/cm³ .

The density of substance is more than water so the substance sinks in the water.