Section 4: Soil and Water Conservation Engineering
Soil Mechanics
Subtopic: Engineering properties of soils
Question Statement:
Capillary water is held in the soil due to
Options:
(A) absorption force
(B) surface tension force
(C) gravitational force
(D) osmotic force
Official Answer Key:
B
Step-by-Step Solution & Explanation
Capillary water is the water retained in the fine pores of soil against the pull of gravity by surface-tension forces acting at the air–water–soil-particle interfaces (capillary menisci), which draw and hold water in narrow pore spaces exactly as in a capillary tube. This distinguishes capillary water from gravitational water (drains freely under gravity, option C) and hygroscopic/adsorbed water (held by adsorption forces at particle surfaces, option A). Hence option (B), surface tension force, is correct.
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.