WorksheetsDay 29-Oct 17-Worksheet-Btech-Particle size analysis
Total questions: 15
Worksheet time: 11mins
According to Stokes’ law, the terminal velocity of a soil particle during sedimentation is proportional to —
Square of particle diameter
Cube of particle diameter
Reciprocal of particle diameter
None
In hydrometer test, effective depth (He) is constant with time.
True
False
Stokes’ law becomes invalid when particle size < 0.2 micron due to Brownian movement.
True
False
Assertion (A): Stokes’ law can be applied to all sizes of soil particles. Reason (R): Because terminal velocity is independent of particle size.
A is true, R is true
A is true, R is false
A is false, R is true
A is false, R is false
The finest sieve used in dry sieve analysis = (a) sieve.
According to Stokes’ law, at…………. the upward forces are equal to the downward force of gravity.
(a)
The dispersing agent used in sedimentation analysis is __________ gm of ___ + __________ gm of ______ per litre of water.
(a)
Match the following
Sieve Analysis
Used for coarse-grained soil > 75 µm
Hydrometer Method
Used for fine-grained soil <75 µm
Pipette method
Used for precise sedimentation measureme
Casagrande Apparatus
Determines consistency limits
In hydrometer analysis, the effective depth (He) is measured as the distance between —
(a)
A soil has more than 50 % passing 75 µm sieve. According to the Indian Standard Classification System (IS 1498), it is classified as —
(a)
A soil particle with specific gravity 2.7 settles in water at 27°C (viscosity = 0.00894 poise) with a terminal velocity of 0.12 mm/sec.
Find the particle diameter in mm.
Take g = 9.81 m/s² and unit weight of water = 9.8 kN/m³.
(a)
During a hydrometer analysis, the following readings were observed:
Observed hydrometer reading = 30
Meniscus correction = 1
Temperature correction = 0.5 (assume test temperature is less than calibration temperature)
Dispersing agent correction = 0.8
Find the corrected hydrometer reading (R).
(a)
Which of the following statements regarding sieve analysis is CORRECT?
Wet sieve analysis is used only for cohesive clay soils
Wet sieve analysis is required when fine fraction (<75 μm) exceeds 5–10%
Coarse sieve analysis alone gives accurate gradation for silty soils
Sieves are arranged with smallest opening at the top
In the hydrometer method, the larger soil particles settle first because their terminal velocity is lower as per Stokes’ law
True
False
A 1000 g soil sample is sieved. Weights retained:
4.75 mm = 50 g, 2.36 mm = 150 g, 1.18 mm = 300 g, 600 μm = 200 g, 300 μm = 180 g, 150 μm = 100 g, pan = 20 g.
Find % finer than 600 μm.
(a)