# Geotechnical Engineering Questions and Answers – Soils Classification – Specific Surface

This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Soils Classification – Specific Surface”.

1. Specific surface is termed as __________
a) Total volume of soil particles
b) Total area of soil particles
c) Total surface area in a unit mass
d) Ratio of total surface to the total volume

Explanation: Specific surface is usually defined as the total surface area of the soil particle in a unit mass.

2. Specific surface of the soil particle increase very rapidly, as the grain size ____________
a) Increases
b) Decreases
c) Bulges
d) None of the mentioned

Explanation: The subdivision of a mass yields greater surface area than the same mass itself. The specific surface of a mass increases as the grain size decreases.

3. A factor, which is important for the magnitude of specific surface of soil particles is__________
a) Grain shape
b) Grain size
c) Both size and shape
d) Grain molecular structure

Explanation: Specific surface varies for different shapes of particle having the same mass. Hence grain shape is important factor for determining specific surface.

4. The specific surface of a soil particle will be ___________
a) Proportional to inter-molecular surface
b) Inversely proportional to electric force
c) Proportional to the compressive force
d) Directly proportional to electric force

Explanation: The electrical force responsible for inter-particle effect is proportional to the specific surface.

5. The harmonic diameter, can be found out by using __________
a) kozney’s method
b) casagrande method
c) Skempton’s method
d) Atterberg method

Explanation: The harmonic diameter DH can be found by using kozney’s method using the formula
F=6/ρs×1/Dn.

6. Specific surface of a soil is related with __________
a) Chemical properties of the soil
b) Physical properties of the soil
c) General characteristic of the soil
d) All of the mentioned

Explanation: As specific surface is associated with surface characteristics of a particle, therefore it is related with physical properties.

7. Microscopic soil particles have a very ___________
a) Larger specific surface
b) A larger volume
c) Small specific surface
d) Larger diameter

Explanation: As the specific surface increases as the size of the grain decreases. Therefore Microscopic particles have a large specific surface.

8. Specific surface(SS) can also expressed as ________
a) Surface area of the particle per unit volume
b) Physical properties of the soil
c) Moisture content of the soil
d) None of the mentioned

Explanation: From the expression, specific surface = surface area of particle/volume of the particle, it can be seen that specific surface is the surface area of a particle.

9. Permeability of the soil depends on __________
a) Size of the soil particle
b) Moisture present in soil
c) Specific surface of the soil particle
d) Density of the soil

Explanation: Permeability of soil greatly depends on the specific surface of the soil because of the viscous effects associated with surface characteristics of the grains.

10. Chemical activity of a clay mineral depends on __________
a) Electric charge
b) Surface area
c) Compactness
d) Unit mass

Explanation: The chemical activity of the clay mineral depends upon the surface area, because of the electrical charge of clay minerals is high per unit mass.

Sanfoundry Global Education & Learning Series – Geotechnical Engineering.

To practice all areas of Geotechnical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.