Permeability MCQ with answer and solution

Concept

In Darcy's law v = k i, the constant k is the coefficient of permeability.

Formula

v = k i ; Q = k i A

Step-by-step solution

1. Darcy's law: discharge velocity v is proportional to hydraulic gradient i. 2. So v = k i, where k is the constant of proportionality. 3. This k is called the coefficient of permeability (hydraulic conductivity). 4. So the answer is (C).

Explanation

Darcy's law says flow velocity through soil is proportional to hydraulic gradient. The constant in this law is k, the coefficient of permeability. It has units of velocity, like cm/s or m/s.

Why the other options are wrong

A: Liquefaction has no Darcy constant. B: Coefficient of compressibility (a_v) belongs to consolidation, not Darcy's law. D: Compaction is studied with the Proctor test, not Darcy's law.

Shortcut

Darcy = flow of water = permeability.

Common mistake

Thinking k has no units. k has units of velocity (m/s).