Test: Physical Quantities and Measurement - Class 7 MCQ

As the temperature of liquids increases, their volume generally expands while their mass remains constant, leading to a decrease in density. This is why hot liquids are less dense than cold ones.

The area of a rectangle is calculated using the formula: Area = Length × Breadth. This allows for the determination of the total surface area covered by the rectangle.

The primary unit of area in the SI system is the square meter (m²), which represents the area of a square with each side measuring one meter. This unit is commonly used for measuring larger surfaces, such as rooms or fields.

The average speed is calculated by dividing the total distance by the total time. Thus, Average Speed = 120 km / 2 h = 60 km/h.

Density is calculated by dividing mass by volume. For this object, Density = 50 g / 25 cm³ = 2 g/cm³.

The new liquid level would be 70 cm³, calculated by adding the 20 cm³ of liquid to the original 50 cm³ level (50 cm³ + 20 cm³ = 70 cm³).

The volume of a cylinder is calculated using the formula: Volume = π × Radius² × Height. This formula accounts for the circular base and the height of the cylinder.

The correct relationship is Mass = Volume × Density. This formula allows for calculating any one of these quantities if the other two are known, emphasizing the direct connection between them in physical science.

To calculate density, you need two measurements: mass and volume. Density is defined as the mass of an object divided by its volume (Density = Mass / Volume).

It's crucial to ensure that the solid is completely submerged in the liquid to accurately measure the volume it displaces. This guarantees that the measurement reflects the true volume of the solid.

The volume of a cube is calculated by cubing the length of one side. For a cube with a side length of 3 cm: Volume = 3 cm × 3 cm × 3 cm = 27 cm³.

Speed is defined as the distance an object travels over a specific period of time. It's calculated using the formula: Speed = Distance / Time, highlighting how quickly an object moves.

The area of the table can be calculated using the formula: Area = Length × Width = 1.5 m × 0.75 m = 1.125 m².

The square centimeter (cm²) is the most appropriate unit for measuring small areas, like that of a coin. It provides a more convenient scale compared to larger units such as square meters.

One square meter is equal to 10,000 square centimeters (cm²). This conversion is derived from the fact that there are 100 centimeters in a meter, thus 1 m² = 100 cm × 100 cm = 10,000 cm².