Maharashtra State PSC Model Paper 3

Concept:

Density:

• The mass density or density of a material is defined as its mass per unit volume.
• The symbol most often used for density is 'ρ' (rho).
• Mathematical Expression is

• The density depends on external factors such as temperature and pressure.
• Aso, density depends on the nature of the substance.
• When the density of a substance is lower than that of water, it tends to float, whereas when the density of a substance is greater than water, it sinks into the water.
• This is illustrated below:

• Object Q has density > water, hence it sinks.
• Object R has density < water, hence it floats.

Explanation:

• Metals generally are hard solids and have high density.
• Hence, most metals like iron, copper, steel will float on water.
• However, some metals which are soft like sodium, have low density.
• Having a lower density than water, sodium tends to float on it.

Hence, the metal that will float on water is Sodium (Na).