Void ratio of a soil is 0.9. Its porosity shall be:

📝 Detailed Explanation

Given: e = 0.9. Using n = e/(1+e) = 0.9/1.9 = 0.4737, matching option (b) 0.47.

💡 Key Concepts for Students

• Another direct application of n = e/(1+e) — by this point in the topic this conversion should be second nature.
• A void ratio of 0.9 is on the higher side, typical of loose sands or moderately loose fine-grained soils rather than dense, well-compacted material.
• As a quick mental check: for e close to 1, n is always fairly close to 0.5 (50%), since n = e/(1+e) ≈ 1/2 when e ≈ 1.
• Keep in mind that n and e describe the same physical void space, just normalized against different reference volumes (total volume vs. solids volume).