Units and Measurements

Ans.2.1

(a) The volume of a cube of side 1 ${cm}^3$ is equal to ${10}^{-6}{m}^3$

The volume of the cube = 1 cm * 1 cm * 1 cm = 1 cm³

1 cm3 = 1 * 10^-6 m³

(b) The surface area of a solid cylinder of radius 2.0 cm and height 10.0 cm is equal to1.25 * 10⁴ (mm)²

The surface area of a solid cylinder = 2? r (r+)h, where r = 2.0 cm = 20 mm, h = 10 cm = 100 mmSurface area = 2 * 22/7 * 20 * (100 +20) ${mm}^2$ = 1.51 * ${10}^4$ ${mm}^2$

(c) A vehicle moving with a speed of 18 km h^–1 covers 5 m in 1 s

Vehicle speed = 18 km/h = 18000/3600 m/s = 5 m/s

(d) The relative density of lead is 11.3. Its density is 11.3 g cm^–3 or 11.3 * 10³.kg m^–3.

Relative density or Specific gravity = Density of the subject / density of water

Density of water = 1 gm/cc= 10^-3 / 10^-6