Quiz: Civil Engineering
Exam: GATE
Topic: Miscellaneous
Each question carries 2 marks
Negative marking: 1/3 mark
Time: 12 Minutes
Q1. The water content of a saturated soil and the specific gravity of soil solids were found to be 30% and 2.70, respectively. Assuming the unit weight of water to be 10 kN/m³, the saturated unit weight (kN/m³) and the void ratio of the soil are
(a) 19.4, 0.81
(b) 18.5, 0.30
(c) 19.4, 0.45
(d) 18.5, 0.45
Q2. If a pipe of diameter 30 cm. running full of water with velocity 100 m/sec is changed by a pipe of diameter 15 cm, then the velocity of water flowing through the pipe will be
(a) 50 m/sec
(b) 100 m/sec
(c) 200 m/sec
(d) 400 m/sec
Q3. A 4-hour rainfall in a catchment of 250 sq.km, produces rainfall depth of 6.2 cm and 5.0 cm in successive 2-hour unit period. Assuming the ϕ – index of the soil to be 1.2 cm/hour, the runoff volume in hectare meter will be?
(a) 2200
(b) 1600
(c) 22
(d) 16
Q4. The concrete having a slump of 6.5 cm, is said to be:
(a) Semi-plastic
(b) Plastic
(c) Dry
(d) Earth moist
Q5. If the depth is 8.64 cm on a field over a base period of 10 days, then the duty is
(a) 10 hec per cu. m/s
(b) 864 hec per cu. m/s
(c) 1000 hec per cu. m/s
(d) 1200 hec per cu. m/s
Solutions
S1. Ans.(a)
Sol. S = 100% = 1
G = 2.7
w = 30% = 0.3
e = ?
γ_sat = ?
We know,
Se = wG
1 × e = 0.3 × 2.7
▭( e=0.81 )
And
γ_sat=((G+e)/(1+e) ) γω
=((2.7+0.81)/(1+0.81))×10
▭(γ_sat=19.4 kN\/m^3 )
S2. Ans.(d)
Sol. given,
d_1=30 cm
V_1=100m\/sec
d_2=15 cm
V_2= ?
By continuity equation
A_1 V_1=A_2 V_2
π/4 (d_1 )^2.V_1=π/4 (d_2 )^2.V_2
(30)^2×100=(15)^2×V_2
▭(V_2=400 m\/sec )
S3. Ans.(b)
Sol.
| Time(hour) | 0-2 | 2-4 |
| Rainfall (Cm) | 6.2 | 5.0 |
ϕ-index=1.2 cm\/hour
A=250 km^2=250×10^(6 ) m^2
We know,
ϕ-index=(P-Q)/t
Where,
P=Precipitation\Rainfall
t=Duration of rainfall
Q = Runoff
1.2=((6.2+5)-Q)/4
Q=11.2-4.8
▭(Q=6.4 cm)
Runoff volume = total runoff × Area of catchment
=6.4×10^(-2)×250×10^6
=1600×10^4 m^3
=1600 ha-m (∵1hecatare=10^(4 ) m^2 )
S4. Ans.(b)
Sol.
| Degree of workability | Consistency | Slump (mm.) |
| Extremely low | Moist Earth | 0 |
| Very low | Very Dry | 0 – 25 |
| Low | Dry | 25 – 50 |
| Medium | Plastic | 50 – 100 |
| High | Semi – Fluid | 100 – 175 |
S5. Ans.(c)
Sol. Given,
∆ =8.64 cm
B=10 days
D= ?
We know,
D=864B/∆
=(864×10)/8.64
▭(D=1000 hec. per cumecs)
