DFCCIL'21 CE : Weekly Practices Quiz: 18.07.2021

Quiz: Civil Engineering
Exam: DFCCIL
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 12 Minutes

Q1. If the chain line which runs along N-S direction is horizontal and the ground in E-W direction is slopping ________.
(a) It is possible to set offsets correctly on east side
(b) It is not possible to set offsets correctly on east side
(c) It is not possible to set offsets correctly on west side
(d) It is possible to set offsets correctly on both sides

Q2. Webster’s method is used for:
(a) Road marking
(b) Marking centerline of the road
(c) Determine design traffic volume
(d) Determine optimum signal cycle

Q3. A waste water sample of 2 ml is made upto 300 ml is BOD with distilled water Initial DO of the sample is 8mg/l and after 5 days it is 28mg/l. What is its BOD?
(a) 894 mg/l
(b) 900 mg/l
(c) 300 mg/l
(d) 1200 mg/l

Q4. A sand deposit has a porosity of 1/3 and its specific gravity is 2.5. The critical hydraulic gradient to cause sand boiling in the stratum will be
(a) 1.5
(b) 1.25
(c) 1.0
(d) 0.75

Q5. Consider the following statements:
The use of super plasticizers as admixture.
1. increases compressive strength of concrete
2. permits lower water-cement ratio, thereby strength is increased
3. reduces the setting time of concrete
4. permits lower cement content, thereby strength is increased
which of the statements given above is/are correct?
(a) 1 and 3 only
(b) 3 and 4 only
(c) 1, 3 and 4 only
(d) 2 only

Q6. As per IS (Indian Standard) specifications, the minimum number of longitudinal bars provided in a column shall be ………… in rectangular columns and ………… in circular columns.
(a) 6, 4
(b) 4, 6
(c) 4, 8
(d) 6, 8

Q7. What is the value of the slope required for coning of the wheel?
(a) 1 in 10
(b) 1 in 15
(c) 1 in 20
(d) 1 in 25

Q8. If a load of 40 KN is applied in a compressive manner on a rod whose cross section is 10 mm ×20mm, then what will be the compressive stress on the rod in MPa?
(a) 0.2
(b) 2
(c) 20
(d) 200

Q9. Estimation of Peak flood discharge for a catchment measuring 180 sq. km is done using Dicken’s formula with a coefficient C = 16. The Peak flood discharge would be:
(a) 493 m³/s
(b) 1246 m³/s
(c) 786 m³/s
(d) 2160 m³/s

Q10. The stream function Ψ=x^3-y^3 is observed for a two-dimensional flow field. What is the Magnitude of the velocity at point (1, -1)?
(a) 4.24
(b) 2.83
(c) 0
(d) -2.83

Q11. The property of a material by virtue of which it can be beaten or rolled into plates is called
(a) Malleability
(b) Elasticity
(c) Plasticity
(d) Ductility

Q12. The pressure within the cylinder of a hydraulic press is 9 MPa. The inside diameter of the cylinder is 500 mm. If the permissible tensile stress is 180 N/mm², the minimum wall thickness of the cylinder is:
(a) 12.5 mm
(b) 16 mm
(c) 9 mm
(d) 18 mm

Solutions

S1. Ans.(d)
Sol. In chain surveying only linear measurements are made that is lengths are only measured by chain or tape. Chain surveying is the simplest and the most accurate kind of surveying. If the chain line which runs along N-S direction is horizontal and the ground in E-W direction is slopping is possible to set offsets correctly on both sides.

S2. Ans.(d)
Sol. Webster’s method is used for determining optimum signal cycle length (C_O) and it is given by according to Webster’s method–

▭(C_O=(1.5L+5)/(1-Y))
L = Total lost time in a cycle length
Y = sum of critical flow rate for all phases

S3. Ans.(b)
Sol. Given, volume of diluted sample = 300 ml.
Initial volume of test sample = 2 ml.
Initial dissolved oxygen (DOi)= 8 mg/l
Final dissolved oxygen (DO_F)= 2 mg/l.
▭(BOD=(DOi-DO_F )×Dilution factor)
Dilution factor = (volume of diluted sample)/(Initial volume of test sample)
= 300/2
= 150
BOD= (8-2) ×150
= 900 mg/l.

S4. Ans.(c)
Sol. porosity (n) = 1/3
G = 2.5
Critical hydraulic gradient (i_c) =?
e = n/(1-n )=(1\/3)/(2\/3)=0.5
▭(e=0.5)
i_c=(G-1)/(1+e)=(2.5-1)/(1+0.5)=1.5/1.5
▭(i_c=1 )

S5. Ans.(d)
Sol. Super-Plasticizer → These are the modified version of plasticizers. They reduce the quantity of mixing water and increase resistance to freezing and thawing. They increase consistency and workability of concrete. They permit lower water cement ratio, there by strength is increased.
Ex. Modified lignosulphonate, sulphonated melanin formaldehyde etc.

S6. Ans.(b)
Sol. Minimum number of longitudinal bars is 4 in rectangular column & 6 for circular column.

S7. Ans.(c)
Sol. The value of the slope required for coning of the wheel is 1 in 20.

S8. Ans.(d)
Sol. Given,
P=40 kN=40×10^3 N
A=10×20 mm^2
σ= ?
σ=P/A
=(40×10^3)/(10×20)
▭(σ=200 MPa)

S9. Ans.(c)
Sol. Peak flood discharge given by Dicken formula-
Q=CA^(3/4)
Where Q= Peak flood discharge (m³/sec)
C= Dicken’s coefficient
A= Area in km²
Now given C= 16, A= 180 km²
Then Q= 16 (180)3/4
Q= 786.27 m³/sec

S10. Ans.(a)
Sol. u=-dψ/dy
u=-d/dy [x^3-y^3 ]= 3y^2
u (1,-1)= 3(-1)^2= 3
v=dψ/dx= d/dx [x^3-y^3 )= 3x^2
v(1,-1)=3(1)^2= 3
V=√(u^2+v^2 )
= √(3^2+3^2 )
=4.24

S11. Ans.(a)
Sol. Malleability is the property of material allows it to expand in all direction without rupture or it is the property of a material by virtue of which it can be beaten or rolled into plates.

S12. Ans.(a)
Sol. Maximum stress inside thin cylinder.
σ_ind= Pd/2t
180 = (9×500)/2t
t = 12.5 mm