MCQ Detailed View

Density is defined as the mass of a substance per unit volume. It is a fundamental physical property that describes how closely packed the particles of a material are. The density of pure water at standard temperature and pressure (4°C and 1 atmosphere) is 1 gram per cubic centimeter (1 g/cm³) or 1000 kilograms per cubic meter (1000 kg/m³) in SI units.

This means that 1 cubic centimeter (1 cm³) of pure water has a mass of 1 gram. This value is often used as a reference point for comparing the density of other substances. Materials with densities higher than 1 g/cm³ sink in water, while those with lower densities float. For example, ice has a density of about 0.92 g/cm³, which is why it floats on water.

The density of water can vary slightly depending on temperature and pressure. As water is heated, it expands slightly, reducing its density. At very high pressures, its density increases. However, under normal conditions, 1 g/cm³ is considered its standard density.

The other options in this question are incorrect:

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  1.5 g/cm³ and 2 g/cm³ are much higher than water's actual density and correspond to denser substances like saltwater or metals.

  
  


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  None of these is incorrect because water’s density is well established as 1 g/cm³.

  
  

Understanding water's density is essential in many areas of physics, chemistry, engineering, and environmental science. It plays a key role in buoyancy, hydrodynamics, and fluid mechanics, and is fundamental in explaining why certain objects float or sink.

This question belongs to Physics, as it deals with a measurable physical property of matter, specifically the relationship between mass and volume of water.