The mass of a lead piece is 115 g. When it is immersed into a measuring cylinder, the water level rises from 20 mL mark to 30 mL mark. Find:

(i) the volume of the lead piece,

(ii) the density of the lead in kg m^-3.

(i) Mass = 115 g;
Initial volume V₁ = 20 mL;
Final volume V₂ = 30 mL;
Volume of lead piece = V₂ - V₁ = 30 - 20 = 10 mL

1 mL = 1 cm³
10 mL = 10 cm³

So, volume of the lead piece = 10 cm³.

(ii) Density = ? $\text{Density} = \dfrac{\text{Mass}}{\text{Volume}} \\[1em] \text{Density} = \dfrac{\text{115}}{\text{10}} = 11.5 \text{g cm}^{3}$

1 g cm^-3 = 1000 kg m^-3
11.5 g cm^-3 = 1000 x 11.5 = 11500 kg m^-3

So, density of lead = 11500 kg m^-3.