Geotechnical Engineering Questions and Answers – Specific Surface

Geotechnical Engineering Objective Questions

This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “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

Answer is C)
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

Answer is B)
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

Answer is A)
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

Answer is D)
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

Answer is A)
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

Answer is B)
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

Answer is C)
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

Answer is A)
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

Answer is C)
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

... Answer is B)
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.