Geotechnical Engineering Questions and answers – Sedimentation Analysis

Geotechnical Engineering Objective Questions

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

1. In sedimentation analysis, the soil fraction should be of what micron size, so as to be kept in a liquid medium (water).

A) 75
B) 83
C) 57
D) 70

Answer is A)
According to Indian standards the soil fraction is set as 75 microns to be used in a liquid medium.

2. The sedimentation analysis is done with the help of________

A) Hydrometer and Pipette
B) Sieve
C) All of the mentioned
D) None of the mentioned

Answer is A)
Both the hydrometer and pipette method can be used for taking sedimentation analysis.

3. The time for a particle to settle, of diameter 0.06 through a height of 10 cm is_________

A) 25.8 s
B) 42 m 59 s
C) 3 m 52 s
D) 42.8 s

Answer is A)
Explanation: Based on the time of settlement of particles of various diameters it is found that minimum time of 25.8 s is needed for a particle to settle of diameter 0.006 mm.

4. Which of the following assumptions is wrong, with respect to sedimentation analysis?

A) The soil particles are spherical
B) Particle settle independent of other particles do not have any effect on its velocity of settlements
C) Soil particles has different specific gravity
D) The walls of jar, in which the suspension is kept do not affect the settlement

Answer is C)
Explanation: In sedimentation analysis, soil particle has average specific gravity.

5. The sedimentation analysis is based on _________ law.

A) Stoke
B) Cullman’s
C) Rankine’s
D) None of the mentioned

Answer is A)
Explanation: The sedimentation analysis is based on stokes law according to which the velocity at which the grains settles down depend on shape, size, weight of grain.

6. In the formula, f=105√(300 ɳ/(g-1)Vw), the factor ɳ depends on__________

A) pressure
B) Velocity
C) Temperature
D) Specific gravity

Answer is C)
Explanation: Since ɳ=viscosity of water/liquid, it can be affected by temperature.

7. The lower limit of particle size allowed in sedimentation analysis is ________

A) 0.0002 mm
B) 0.04 mm
C) 0.074 mm
D) 0.0004 mm

Answer is A)
Explanation: The particle smaller than 0.0002 mm is affected by Brownian movement and stokes law remains no longer valid.

8. 1 poise is equivalent to _________

A) 0.5 NS/m2
B) 0.1 NS/ m2
C) 10-4 K NS/ m2
D) 0.8 NS/ m2

Answer is B)
Explanation: As,1 poise =1/10 NS/ m2 1 poise =0.1 NS/ m2.

9. The unit weight of water in v=(2/g)r2(Vs-Vw/ɳ) is taken as ________

A) 9.81 kn/m2
B) 98.1 n/m2
C) 0.981 kn/m2
D) 9.81 n/m3

Answer is A)
Explanation:The constant value of unit weight of water/liquid is taken as γw=9.81 kn/m2.

10. Viscosity of water/liquid (ɳ) is expressed in ________

A) KN-s/m3
B) Ns/m2
C) KN-s/m2
D) Ns/m

Answer is C)
Explanation: The viscosity of distilled water in sedimentation analysis is taken as 0.00855 KN-s/m2.