If the relative density of copper is 8.4 then what is the density of copper in the SI unit?

Relative density of copper = 8.4

Relative density $=\frac{\text{ Density of Copper }}{\text{ Density of water }}$

The density of Copper = Relative density of Copper × Density of water

The density of water in SI unit= 10³ kg m^–3

$\therefore$The density of Copper = 8.4 × 10³ kg m^–3 = 8400 kg/m³.