A soil sample has porosity 25%. Calculate its void ratio.

🔑 Concept
The relation between void ratio and porosity of a soil sample is given as:
n = e / (1 + e)
Where
n is porosity and e is void ratio.

📝 Calculation
Given: n = 0.25
Using the formula:
n = e / (1 + e)
Substitute the value of n:
0.25 = e / (1 + e)
Solve for e:
e = 0.34

📌 Important Points

Porosity is the total volume of voids in a soil sample expressed as a percentage of the total volume of the soil sample, while void ratio is the ratio of the volume of voids to the volume of solids in the soil sample.
Porosity is always less than 100%, but void ratio may be less than 1 or greater than or equal to 1.