What is the porosity percentage if the particle density of soil is 2.6 and bulk density is 1.3

Answer: Option C

If the particle density of soil is 2.6 and bulk density is 1.3 then the porosity percentage will be:
$$\begin{array}{rl}& \text{Soil porosity}=\left(1-\frac{\text{Bulk Density}}{\text{Particle Density}}\right)\times 100\\ & =\left(1-\frac{2.6}{1.3}\right)\times 100\\ & =0.5\times 100\\ & =50\%\end{array}$$