Quiz: Civil Engineering 28 Oct 2020

Quiz: Civil Engineering
Exam: SSC-JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. A soil has plastic limit of 20% and plasticity index of 40%. If the natural water content of the soil is 34%, then the consistency index is equal to
(a) 0.35
(b) 0.65
(c) 0.82
(d) 1.00

Q2. Which of the following acts as retarder for the concrete?
(a) Calcium chloride
(b) Gypsum
(c) Calcium stearate
(d) Aluminium powder

Q3. A heterotroph is an organism that obtains
(a) its cell carbon from an inorganic source
(b) its energy from the oxidation of simple inorganic compounds
(c) its cell carbon as well as its energy from organic matter
(d) its energy from a natural ecosystem

Q4. For estimation of painted area of semi corrugated asbestos cement sheets, percentage increase in area above the plain area is _____ .
(a) 0.1
(b) 0.14
(c) 0.2
(d) 0.25

Q5. The critical depth of flow in a most economical triangular channel section for a discharge of 1 m³/sec is given by
(a) (1/9.8)^(1/5)metre
(b) (1/9.8)^(1/3)metre
(c) (1/4.9)^(1/5)metre
(d) (1/4.9)^(1/3)metre

Q6. The water utilized by the plants is available in soils mainly in the form of
(a) Chemical water
(b) Hydroscopic water
(c) Capillary water
(d) Gravity water

Q7. Axial load carrying capacity of RC column of gross area of concrete Ac, area of steel As and permissible stresses δ_c in concrete and δ_s in steel, m – modular ratio is given as:
(a) δ_c A_c+(m–1)δcAs
(b) δ_s As+mδcAs
(c) δcAs+δ_c As
(d) δ_c (Ac-As)+δcAs

Q8. If all the dimensions of a prismatic bar of square cross-section suspended freely from the ceiling of a roof are doubled then the total elongation produced by its own weight will increase.
(a) eight times
(b) four times
(c) three times
(d) two times

Q9. The purpose of stiffeners in a plate girder is to :
(a) take care of bearing stress
(b) increase the moment carrying capacity of the girder
(c) prevent buckling of web plate
(d) reduce the shear stress

Q10. When 1 cm on a map represents 10 m on the ground, the representative fraction of the scale is:
(a) 1/100
(b) 1/10000
(c) 1/1000
(d) 1/10

SOLUTIONS

S1. Ans.(b)
Sol. Given,
W_P=20%
W_n=34%
I_P=40 %
I_C= ?
I_c=(W_L-W_n)/(W_L-W_P )=(W_L-W_n)/I_P
Here,
I_P=40%
W_L-W_P=40%
W_L-20%=40%
W_L=60%
Now,
I_C=(60%-34%)/40
▭(I_C=0.65)

S2. Ans.(b)
Sol. Calcium chloride → Accelerator
Gypsum → Retarder
Calcium stearate → water proofer
Aluminium powder → Air entraining agent

S3. Ans.(c)
Sol. Autotrophs → Derive both material (cell carbon) and energy from inorganic substances.
Heterotrophs → Derive both material (cell carbon) and energy from organic substances.

S4. Ans.(a)
Sol. for estimation of painted area of semi corrugated asbestos cement sheets, percentage increases in area above plain are is 10% or 0.1 and for corrugated steel sheets, the plain area of sheets should be increased by 10% or 0.1.

S5. Ans.(c)
Sol. for most economical triangular channel section, the side slope m = tanθ = tan 45
▭(m=1)
Given, Q = 1 m³/sec.
Now, critical depth for triangular channel
Section –
y_c=((2Q^2)/(gm^2 ))^(1\/5)
=[(2×(1)^2)/(9.8×(1)^2 )]^(1\/5)
▭(y_c=(1/4.9)^(1\/5) metre)

S6. Ans.(c)
Sol. The water utilized by the plants is available in soils mainly in the form of capillary water. Capillary water is responsible for growth of plants while hydroscopic water is attached with the soil particle hence it cannot be extracted by plants.

S7. Ans.(a)
Sol. Axial load carrying capacity for RC-column is given by-
▭(P=δ_C A_C+(m-1) δ_c A_S )
Where, δ_C = Permissible stress in concrete
A_C = Gross area of concrete
δ_S = Permissible stress in steel
A_S = Area of steel
m = modular ratio

S8. Ans.(b)
Sol. Total elongation in a prismatic bar due to its self weight is given by-
▭(∆L=(yL^2)/2E)
Now, length of bar is doubles then Total elongation in bar will be-
∆L^’=(γ×(2L)^2)/2E
=4×(γL^2)/2E
▭(∆L^’=4∆L)

S9. Ans.(c)
Sol. Stiffeners are typically plate welded to the web. These plates increase the moment of inertia of plate girder which enhance the rigidity in turns it prevent buckling of web plate. To increase the moment carrying capacity of the girder, we provide the cover plates on flange.

S10. Ans.(c)
Sol. Representative fraction (RF) of the scale is
1cm → 10m.
1cm → 1000 cm.
▭(RF⇒1/1000)

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