QUIZ : CIVIL ENGINEERING (09-02-2021)

Quiz: Civil Engineering

Exam: SSC-JE

Topic: MISCELLANEOUS

Each question carries 1 mark

Negative marking: 1/4 mark

Time: 10 Minutes

Q1.     Which is the best sewer material to resist hydrogen sulphide corrosion?

(a) Glazed stoneware

(b) Glazed earthenware

(c) RCC

(d) Brick masonry

Q2.     The threshold odour number (TON) for a water sample of 40 ml, diluted to standard 200 ml mixture, in which odour is just barely detectable to the sense of smell is,

(a) 8

(b) 5

(c) 50

(d) None of these

Q3.     If pH value of solution A is 4 and that of solution B is 5, then the hydrogen-ion concentration of solution

(a) A is ten time higher than that of B

(b) B is double than that of A

(c) A is ten times lesser than that of B

(d) A is double that that of B

Q4.     If the hardness of a sample of water, expressed in ppm of calcium carbonate is more than 300, the sample will be treated as

(a) hard water

(b) moderately hard water

(c) soft water

(d) very hard water

Q5.     Consider the following statements:

In a water supply system

1. drain valves are provided at elevated or higher, points to remove accumulated air.

2. reflux valve allows flow in one direction only

3. drain valves are provided at low points to remove silt and other deposits.

Which of these statements is/are correct?

(a) 1, 2 and 3

(b) 2 only

(c) 2 and 3 only

(d) 3 only

Q6.     Deflection of prestressed concrete beam is excessive in the

(a) Pre-cracking stage

(b) Plastic stage

(c) Post-cracking stage

(d) none of the above

Q7.     Shallow ponds in which dissolved oxygen is present at all depths are called

(a) aerobic lagoons

(b) aerobic ponds

(c) facultative lagoons

(d) facultative ponds

Q8.     A u-tube manometer is used to measure the pressure in an oil pipe A as shown in the figure. The specific gravity of oil of 0.8 and that of mercury is 13.6. the equivalent gauge pressure is nearly.

(a) 8.53 kN/m²

(b) 11.76 kN/m²

(c) 13.34 kN/m²

(d) 15.00 kN/m²

Q9.     If flow velocity in x and y directions are given by u = 2x + 3y and v =– 2y. The circulation around the circle of radius 2 unit will be

(a) -8π

(b) -10π

(c) -12π

(d) -14π

Q10.  A stream function is given by,  The flow rate across a line joining points A(3, 0) and B(0, 2) is

(a) 0.4 units

(b) 1.1 units

(c) 4 units

(d) 5 units

SOLUTION

S1. Ans.(a)
Sol. Glazed stoneware or vertified clay pipes have the advantage of being highly resistant to sulphide corrosion.

S2. Ans.(b)
Sol. Threshold odour number represent the dilution ratio at which the odour is hardly detectable.
T.O.N. = 200/40 = 5

S3. Ans.(a)
Sol. p^H = –log_10⁡[H^+ ]
[H^+ ]_A = 10^(–4)
[H^+ ]_B = 10^(–5)
[H^+ ]_A/[H^+ ]_B = 10^(–4)/10^(–5) = 10

S4. Ans.(d)
Sol.
Degree of Hardness Range
Soft <50 mg/l as CaCO_3 Moderately hard 50-150 mg/l as CaCO_3 Hard 150-300 mg/l as CaCO_3 Very Hard > 300 mg/l as CaCO_3

S5. Ans.(a)
Sol. Reciprocating pump gives constant discharge under variable head. It is used for low discharge under variable high heads.

S6. Ans.(c)
Sol. In the past cracking stage, the behavior of the prestress beam is similar to that of reinforced concrete member.

S7. Ans.(b)
Sol. shallow ponds in which dissolved oxygen is present at all depths are called aerobic ponds.

S8. Ans.(b)
Sol. Pressure of ‘A’
= ρ_m gh_1 –ρ_0 gh_2
= 13.6 × 9.81 × 0.1 – 0.8 × 9.81 × 0.2
= 11.77 kN/m^2

S9. Ans.(c)
Sol. u = 2x + 3y
v = –2y
w_z = 1/2 [∂v/∂X – ∂y/∂Y]
= 1/2 [0 – 3]
= (–3)/2
Vorticity = 2 × W_z
= –3
Circulation = Verticity × area
= – 3 × π × r^2 (r = 2)
= – 12 π

S10. Ans.(c)
Sol. Q = | ψ_A – ψ_B |
ψ_A = 2 × 3^2 × 0 + (3 + 1) (0)^2 = 0
ψ_B = 2 × 0^2 × 2 + (0 + 1) (2)^2 = 4
Q = |0 – 4| = 4 unit

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