UPSSSC-JE'21 CE: Daily Practice Quiz. 18-October-2021

Know your strengths and practice your concepts with this quiz on UPSSSC-JE Recruitment 2021. This quiz for UPSSSC-JE Recruitment 2021 is designed specially according to UPSSSC-JE Syllabus 2021.

Quiz: Civil Engineering
Exam: UPSSSC-JE
Topic: MISCELLANEOUS

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 8 Minutes

Q1. A drain carrying sewage of BOD = 200 mg/l and flow rate of 50 m³/sec. joins a river whose upstream BOD is 8 mg/l and flow rate is 500 m³/sec. Assume immediate and complete mixing of drain with the river. What is the estimated downstream BOD of the river flow?
(a) 20.4 mg/l
(b) 25.4 mg/l
(c) 70.4 mg/l
(d) 104.4 mg/l

Q2. A sewer is commonly designed to attain self-cleansing velocity at
(a) Sewer running half full
(b) Peak hourly rate of flow
(c) Minimum hourly rate of flow
(d) Average hourly rate of flow

Q3. Which one of the following would help prevent the escape of foul sewer gases from a water closet
(a) Vent pipe
(b) Gully trap
(c) Air gap
(d) None of these

Q4. Match List-I (Corrections) with List-II (Name) and select the correct answer using the codes given below the lists.
List-I
A. ±∝(T_f-T_s )L
B. (-l)/24 (W/P)^2
C. ±(P_f-P_s )L/AE
D. ±L(1-h/R)
List-II
1. Pull correction
2. Sag correction
3. Temperature correction
4. Mean sea level correction
Codes
(a) A-4, B-1, C-3, D-2
(b) A-1, B-4, C-3, D-2
(c) A-3, B-2, C-1, D-4
(d) A-2, B-3, C-1, D-4

Q5. The following bearing were observed while traversing with a compass, which stations are affected by local attraction?

Line	F.B.	B.B.
AB	104°30’	284°30’
BC	48°15’	226°0’
CD	290°30’	115°15’
DA	180°15’	357°15’

(a) C and D
(b) A and D
(c) A and B
(d) B and C

Q6. Calculate the reduced level (m) of a point A, if the staff reading at point A and Benchmark are 2.9 m and 2.6 m respectively. The reduced level of the benchmark is 100 m.
(a) 97.22
(b) 100.3
(c) 105.3
(d) 99.7

SOLUTION

S1. Ans.(b)
Sol. Given,
BOD of stream (BOD_s) = 200 mg/l
Flow rate of stream (Q_s ) = 50 m^3/sec.
BOD of river (BOD_R ) = 8 mg/l
Flow rate of river (Q_R ) = 500 mg/l
(BOD_mix ) = ?
Now,
BOD_mix=(50×200+500×8)/(50+500)
= 25.45 mg/l

S2. Ans.(c)
Sol. Self-cleansing velocity is such flow velocity as would be sufficient to flush out any deposited solids in the sewer. A sewer is commonly designed to attain the self-cleansing velocity at minimum hourly rate of flow.

S3. Ans.(d)
Sol. Intercepting trap is used to prevent entry of foul sewer gases into the water closet by providing a water seal.

S4. Ans.(c)
Sol. Pull correction → ±(P_f-P_s )L/AE
Sag correction → (-l)/24 (W/P)^2
Temperature correction → ±∝(T_f-T_s )L
Mean sea level correction → ±L(1-h/R)

S5. Ans.(a)
Sol. Since difference of F.B and B.B of line AB differs by 180°. Hence both stations A and B are unaffected by local attraction and station C and D are affected by local attraction.

S6. Ans.(d)
Sol.

Height of collimation of instrument at station P
= RL of Benchmark + B.S. of Benchmark
= 100 + 2.6
= 102.6 m.
RL of A = Height of collimation at P – F.S. at A
= 102.6 – 2.9
= 99.7 m.