GATE QUIZ : CIVIL ENGINEERING (06 MAY 2021)

Quiz: Civil Engineering
Exam: GATE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/3 mark
Time: 15 Minutes

Q1. A rectangular channel 5 m wide is laid on a slope a 0.0004. when the depth of flow in channel is 2m, what is the average boundary shear stress?
(a) 1.55 N/m²
(b) 2.46 N/m²
(c) 3.34 N/m²
(d) 4.36 N/m²

Q2. The sequent depth ratio of a hydraulic jump in a rectangular channel is 15.34 what is Froude number at the beginning of jump?
(a) 10
(b) 11
(c) 12
(d) 13

Q3. At a hydraulic jump, the depth at the two sides are 0.5m and 1.5 m. the head loss in the jump is nearly.
(a) 0.33 m
(b) 0.25 m
(c) 0.46 m
(d) 0.75 m

Q4. Generally, to estimate PMP, P_M = 42.16 D^0.475 is used (P_m is max depth of precipitation, D – duration) what are the units of P_m and D in the equation?
(a) mm, sec
(b) cm, sec
(c) mm, hr
(d) cm, hr

Q5. A 2hr storm on a small catchment area produced rainfall intensities of 3.5 cm/hr and 4.4 cm/hr in successive hours. If the surface runoff due to the storm is 3cm, then the value of ϕ-index is ?
(a) 3.6 cm/hr
(b) 3.5 cm/hr
(c) 2.45 cm/hr
(d) 1.96 cm/hr

Q6. A 4-hr unit hydrograph of a basin can be approximated as a triangle with a base period of 36 hrs and peak ordinate of 200 m³/s what is the area of the basin?
(a) 2592 cm²
(b) 1696 cm²
(c) 3612 cm²
(d) 1296 cm²

Q7. A channel designed by Lacey’s theory has a mean velocity of 1.2 m/s. the silt factor is 1.2. then the hydraulic mean depth will be?
(a) 2.5 m
(b) 3 m
(c) 2.75 m
(d) 3.5 m

Q8. The material in which large deformation is possible before absolute failure by rupture take place, is known as?
(a) Ductile
(b) Plastic
(c) Brittle
(d) Elastic

Q9. In an experiment, it was found that the bulk modulus of a material is equal to its shear modulus. The poison’s ratio is?
(a) 0.125
(b) 0.250
(c) 0.375
(d) 0.500

Q10. In a concrete mix, the fineness modulus of coarse aggregate is 8.2 and the fineness modulus of fine aggregates is 2.4. if the economical value of the fineness modulus of combined aggregate is 6.5, then the proportion of fine aggregate is?
(a) 25%
(b) 25.5%
(c) 29.3%
(d) 28.2%

Solutions

S1. Ans.(d)
Sol. τ_0=γR.S_0
R = A/P = By/(B+2y)
= (5×2)/(5+2×2)=1.11 m
∵τ_0=9810×1.11×0.0004
= 4.36 N/m²

S2. Ans.(b)
Sol. The sequent depth ratio for a rectangular channel is given by
y_2/y_1 =1/2 (-1+√(1+8F_1^2 ))
⇒15.34=1/2 (-1+√(1+8F_1^2 ))
⇒▭(F1=11.195)

S3. Ans.(a)
Sol. Head (os), E_L = (y_2-y_1 )^3/(4y_1 y_2 )
=(1.5-0.5)^3/(4×0.5×1.5)
= 0.33 m

S4. Ans.(d)
Sol. Extreme Rainfall depth (in cm)
P_m = 42.16 D^0.475
Where, D duration of rainfall (om hu)

S5. Ans.(c)
Sol. Total rainfall = 3.5 + 4.4
= 7.9 cm
Effective rainfall = 3 cm
Infiltration = 7.9 – 3 = 4.9 cm
W – index = 4.9/2 = 2.45 cm/hr
As rainfall intensities are greater than W – index, so
W – index =ϕ – index = 2.45 cm/hr

S6. Ans.(d)
Sol.

1/2×Q_P×T_B=A×1/100
⇒A=(100Q_P T_B)/2=(100×200×36×3600)/(2×10^6 )
= 1296 km²

S7. Ans.(b)
Sol. R=5/2 V^2/f
=5/2×〖1.2〗^2/1.2 =3m

S8. Ans.(a)
Sol. Materials in which large deformation before fracture is observed are referred an ductile material whereas material which show sudden fracture are known as brittle materials.

S9. Ans.(a)
Sol. μ=(3k-2G)/(6k+2G)
Given that K = G
⇒ μ=(3K-2K)/(6K+2K)
=K/8K=1/8
= 0.125

S10. Ans.(c)
Sol. The proportion of fine aggregate to the combined aggregate,
R=(P_2- P)/(P_2-P_1 )×100
=(8.2-6.5)/(8.2-2.4)×100
= 29.31 %

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