The relative density of lead is $11.3$. Its density in SI unit is

$\mathrm{Relative} \mathrm{density}=\frac{\mathrm{Density} \mathrm{of} \mathrm{a} \mathrm{substance}}{\mathrm{Density} \mathrm{of} \mathrm{water}}$ 

$\therefore$ Density of lead $=11.3\times 1\times {10}^3 kg m^{-3}$

                              ($\because$ Density of water $=1\times {10}^3 kg m^{-3}$)

$=11.3\times {10}^3 kg m^{-3}=1.13\times {10}^4 kg m^{-3}$