Physical Quantities and Measurement

Magnitude = number of times the unit is contained in the quantity × unit

Measurement is a process of comparison of the given unknown quantity with a fixed known quantity of the same kind called the unit.

The space occupied by an object is called its volume.

Volume of a cube = (one side)^3

Volume of a cuboid = length × breadth × height

Volume of a sphere = (4π/3) × (radius)^3

Volume of a cylinder = π × (radius)^2 × height

Area of a square = (one side)^2

Area of a rectangle = length × breadth

Area of a circle = π × (radius)^2

Surface area of a cylinder = 2π × (radius) × length

Surface area of a sphere = 4π × (radius)^2

The density of a substance is defined as the mass of a unit volume of that substance.

Density = Mass/Volume or d = M/V

1 g cm^-3 = 1000 kg m^-3