# Weirs MCQ – Fluid Mechanics

1. Weirs are normally used to calculate

2. volume
3. velocity
4. discharge

2. How many types of weirs are there based on the shape of the crest?

1. 6
2. 4
3. 5
4. 3

3. A stream has a width of 30m, depth of a 3 m and a mean velocity of 1.25 m/sec. What is the height of a weir to be built on the stream floor so as to cause an afflux of 1 m? Assume value of discharge coefficient as 0.95.

1. 3.594 m
2. 2.787m
3. 4.312 m
4. 1.956 m

4. Discharge over an ogee weir remains the same as that of

1. Sharp crested weir
2. Triangular weir
3. Drowned weir
4. Cipolletti weir

5. The Francis formula for the discharge over cipolletti weir is

1. 1.84 LH1/2
2. 1.84 LH3/2
3. 1.84 LH
4. 1.84 LH5/2

6. The overflowing sheet of water on a weir is called

1. Nappe
3. Crest
4. Upstream

7. Triangular weir is also called

1. trigonometri1c
2. ogee
3. v-notch
4. isolated

8. The weir is always aligned at right angle to the direction of the river flow because

1. it ensure less length of weir
2. it gives good discharging capacity
3. it is economical
4. it ensure less length, good discharge and economical

9. A suppressed sharp crested weir is 0.6 m high and discharges water at a head of 1.2 m. The coefficient of discharge of this weir is

1. 0.701
2. 0.611
3. 0.761
4. 0.736

10. The cipolletti weir is a ___________ weir.

1. Triangular
2. Trapezoidal
3. Circular
4. Rectangular

11. Barrage differs from Weir when

1. major part by gates and minimum or nil part by shutters
2. equal part of pounding by both crest and gates
3. minimum or nil part of pounding by gates and major part by crest
4. major part of pounding by gates and minimum or nil part of crest

12. The discharge over a broad crested weir is maximum when the depth of flow is

1. H/3
2. H/2
3. 2H/3
4. 2H/5

13. A Cipolletti weir is a

1. rectangular weir with sharp edges
2. high triangular notch
3. trapezoidal notch with 45° slopes
4. trapezoidal notch with sides inclined at 1H : 4V

14. For a broad crested weir, if discharge is maximum for available head of 24 m, then what would be the critical depth of weir?

1. 8 m
2. 12 m
3. 16 m
4. 24 m

15. Suppressed weir has

1. crest length less than width of channel
2. crest length more than width of channel
3. crest length equal to width of channel
4. crest length can be less or more than width channel

16. In a Sarda type fall, the rectangular crest, may be used for discharge upto

1. 6 cumecs
2. 10 cumecs
3. 14 cumecs
4. 20 cumecs

17. A weir, generally, uses as a spillway of a dam is

1. submerged weir
2. ogee weir
3. narrow crested weir

18. Aeration of nappe is necessary for which type of weirs?

1. contracted rectangular
2. suppressed weir
3. submerged contracted rectangular
4. triangular

19. Which of the following are the causes of failure of weirs?

1. Rupture of floor due to uplift
2. Rupture of floor due to suction caused by standing wave
3. Scour on the upstream and downstream of the weir
1. i and ii only
2. i and iii only
3. i, ii and iii
4. ii and iii only

20. A Cipolletti weir has a side slope of

1. 1V : 2H
2. 1V: 1H
3. 1H : 2V
4. 1H : 4V

21. When the water level on the downstream side of a weir is above the top surface of a weir, the weir is known as

1. Narrow crested weir