Quiz: Civil Engineering

Exam: GATE

Topic: Miscellaneous

Each question carries 1 mark

Negative marking: 1/3 mark

Time: 15 Minutes

Q1. On an immersed body in a flowing fluid the lift force is

(a) Due to buoyant force

(b) Always in opposite direction to gravity

(c) Due to wake phenomenon

(d) The dynamic fluid force component normal to approach velocity

Q2. Cavitation is caused by

(a) High velocity

(b) Low velocity

(c) High temperature

(d) Low pressure

Q3. The number of π – parameters needed to express the function F(A, V, t, μ, L) = 0

(a) 5

(b) 3

(c) 4

(d) 2

Q4. A wastewater effluent contains 2000 mg/l of total dissolved solids (TDS), TDS (in%) in the present sample is?

(a) 0.05%

(b) 0.1%

(c) 0.2%

(d) 0.4%

Q5. A surface water treatment plant operates with a flow rate of 40 m³/min. the water temperature is 20°C and jar test indicates an optimum alum does of 30 mg/l with flocculation at a ‘Gt’ value of 8 × 10^4 The quantity of alum required for year operation of the plant is?

(a) 380 tonnes

(b) 630 tonnes

(c) 520 tonnes

(d) 210 tonnes

Q6. The re-oxygenation constant for a river stream is 0.25 at 20°C temperature. What will be this value at 35°C pf temperature?

(a) 0.20

(b) 0.26

(c) 0.36

(d) 0.32

Q7. The equivalent sound pressure level (in dB) of four source with noise level of 50 dB, 60 dB, 70dB and 80 dB would be?

(a) 80 dB

(b) 81.45 dB

(c) 82.80 dB

(d) 80 dB

Q8. A distributary irrigates a portion of CCA to grow sugarcane and rice. The average discharge required to grow both the crops are 0.40 cumecs and 0.35 cumeecs respectively. If the time factor is 0.8, the required design capacity of the canal is?

(a) 0.94 cumecs

(b) 0.75 cumecs

(c) 0.86 cumecs

(d) 0.70 cumecs

Q9. Isopleths are the lines on the map joining the point having equal depth of:

(a) Rainfall

(b) Infiltration

(c) Evaporation

(d) Evapotranspiration

Q10. An aerial photograph of a terrain having an average elevation of 1000m is taken at a scale of 1:8000. The focal length of the camera is 15 cm. the altitude of the flight above mean sea level is?

(a) 2225 m

(b) 2525 m

(c) 2000 m

(d) 2200 m

Solutions

S1. Ans.(d)

Sol. The dynamic fluid force component normal to approach velocity or normal to the direction of flow is referred as lift force whereas along the direction of flow or in the direction of approach velocity is referred as drag force

S2. Ans.(d)

Sol. If the pressure of fluid flow drops below the vapour pressure, the gases start to form bubbles and starts flowing with water. If pressure is again increased, these bubbles will burst and form cavities on the pipe surface, the phenomenon is referred as cavitation

S3. Ans.(d)

Sol. f(A, V, t, μ, L) = 0

Total no of variables, m = 5

No of fundamental dimensions n = 3

Total no of π -terms = m – n

= 5 – 3

= 2

S4. Ans.(c)

Sol. 1 kg of water = 1 litre

TDS(%) = (2000×10^(-3) g)/(1 litre)

= (2000×10^(-3) g)/(1000 g )×100=0.2%

S5. Ans.(b)

Sol. Q = 40 m³/min

Gt = 8 × 104

Dose of alum = 30 mg/l

Quantity of Alum required for 1 year operation (annual demand)

=40×10^3×60×24×365×30×10^(-6)

= 630720 kg

= 630.72 tonnes

S6. Ans.(d)

Sol. Kr_((T°C) )=Kr_((20°C) ) [1.016]^(T-20°C)

= 0.25 × [1.016]^(35-20)

= 0.32

S7. Ans.(b)

Sol. L = 20log10 (P_rms/P_0 ) dB

P_0=20μPa

L_1=50 =20 log_10 (P_rms1/(20 μPa))

⇒P_rms=6324.5 μPa

Similarly

P_(rms 2)=20000 μPa

P_rms3=63245.55 μPa

P_rms4=200000 μPa

(P_rms )_equivalent=√((6324.5)^2+(20000)^2+(63245.55)^2+(200000)^2 )

=210807.9685

Leq=20 log_10 (P_rmseq/20)

=20log_10 (210807.9685/20)

= 80.45 dB

S8. Ans.(a)

Sol. Rice is kharif crop and sugarcane is perineal, 30 the total discharge required is sum of both the requirements

∵Design discharge=(Total Discharge)/(Time factor )

=(0.40+0.35)/0.8

= 0.9375 m³/s

S9. Ans.(d)

Sol. Isopleths are the lines on the map through the places, having equal value of the evapotranspiration (PET)

S10. Ans.(d)

Sol. h = 1000 m

Scale = 1:8000

f = 15 cm

Scale = f/(H-h)

⇒ 1/8000=(15×10^(-2))/(H-1000)

⇒ H = 2200 m