# Notches MCQ – Fluid Mechanics

1. Notches are used to measure

1. velocity
2. flow rate
3. pressure
4. all above

2. For which angle of triangular notch the discharge over it is maximum?

1. 45°
2. 30°
3. 90°
4. 60°

3. The discharge over a rectangular notch is

1. inversely proportional to H3/2
2. directly proportional to H3/2
3. inversely proportional to H5/2
4. directly proportion to H5/2

4. Which notch is preferred for measuring the low discharges?

1. triangular notch
2. rectangular notch
3. trapezoidal notch
4. parabolic notch

5. The discharge through a V-notch varies as

1. H
2. H1.5
3. H0.5
4. H2.5

6. The sheet of water flowing through a notch or weir is known as

1. Nappe
2. Crest notch
3. Crested weir
4. Crest

7. In any channel, notch is used to measure the following

1. discharge
2. pressure
3. velocity
4. static energy

8. Discharge Q in a triangular weir varies as

1. H1/2
2. H
3. H3/2
4. H5/2

9. Which notch is preferable for low flow rates?

1. Rectangular
2. Triangular
3. Both Rectangular and Triangular
4. None of these

10. In a 90° triangular notch, the error in the estimated discharge for a given head due to an error of 1% in cutting the vertex angle is

1. 1 %
2. zero
3. π/2 %
4. π %

11. If H is the head, the discharge through a V-notch varies

2. inversely proportional to angle θ
3. inversely proportional to tan θ/2
4. proportional to H5/2

12. The discharge through a V-notch varies with the depth of water H as

1. H1/2
2. H3/2
3. H5/2
4. H-1/2

13. For maximum discharge over a triangular notch, the angle of the notch should be

1. 60°
2. 30°
3. 120°
4. 90°

14. Notch is used for measuring

1. velocity through a small channel
2. rate of flow through a pipe
3. velocity through a pipe
4. rate of flow through a small channel

15. Notch is a device used for measuring

1. rate of flow through pipes
2. rate of flow through a small channel
3. velocity through a pipe
4. velocity through a small channel

16. The rate of flow through a V-notch varies

1. H
2. H1/2
3. H5/2
4. H3/2

17. A triangular notch is more accurate measuring device than a rectangular notch

1. for low flow rates
2. for medium flow rates
3. for high flow rates
4. for all flow rates

18. The discharge over a rectangular notch is

1. directly proportional to H5/2
2. directly proportional to H3/2
3. inversely proportional to H3/2
4. inversely proportional to H5/2

19. The head over a 90° V-notch increases from 0.20 m to 0.40 m. The ratio of the new discharge to the original discharge is

1. 1.414
2. 2.000
3. 4.000
4. more than 4.000

20. The percentage error in the computed discharge over a triangular notch corresponding to an error of 1% in the measurement of the head over the notch, would be

1. 2.5
2. 2
3. 2.2
4. 1.5