Physical Quantities and Measurement - Free MCQ Practice Test with solutions,

An object with a density of 0.5 g/cm³ will float in a liquid with a density of 0.8 g/cm³ because it is less dense than the liquid. This principle is essential in applications involving flotation and buoyancy.

The relative density of a substance with a density of 7.8 g/cm³ compared to water (1 g/cm³) is 7.8. This means that the substance is 7.8 times denser than water, explaining why it would sink.

When the mass of an object increases while the volume stays the same, the density increases. This is because density is directly proportional to mass; as mass increases, density must also increase if volume does not change.

The volume of an irregular solid can be determined using the displacement method. This involves submerging the solid in water and measuring the volume of water displaced, which equals the volume of the solid.

The density of water decreases as it freezes, which is why ice floats on water. This decrease in density is unusual for substances, as most become denser when solidified.

A density bottle is significant because it ensures that a fixed volume of liquid is measured. This precision is vital for accurately calculating the density of the liquid in question.

Ice, with a density of 0.917 g/cm³, will float in water because its density is less than that of water (1 g/cm³). This characteristic of ice is crucial for aquatic life, as it insulates the water below.

Generally, the density of a substance decreases when it is heated because its volume tends to increase. However, water is an exception, as its density increases when heated from 0°C to 4°C before decreasing at higher temperatures.

The relative density of a substance is the ratio of its density to the density of water. This helps in determining how a substance will behave in water, such as whether it will float or sink.

The SI unit of density is kg/m³. This unit expresses mass in kilograms and volume in cubic meters, providing a standard way to quantify how dense a substance is.

Objects with higher density than water sink because the buoyant force exerted by the water is insufficient to support them. The weight of the object exceeds the upward buoyant force, causing it to sink.

Submarines use the principle of buoyancy by controlling the density of their internal air tanks. When they fill these tanks with water, their density increases, causing them to sink. Conversely, when filled with air, their density decreases, allowing them to rise.

Cork has a density of approximately 0.25 g/cm³, which is less than that of water (1 g/cm³). This lower density allows cork to float on water, making it useful in various applications.

An object will sink in water if its density is greater than that of water (1 g/cm³). Conversely, if its density is less than water, it will float. This principle is fundamental to understanding buoyancy.

Density is defined as the mass of an object divided by its volume. This relationship helps us understand how tightly packed the matter in an object is, which is crucial in determining whether it will float or sink in a liquid.