MCQOPTIONS
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MCQOPTIONS
This section includes 48 Mcqs, each offering curated multiple-choice questions to sharpen your Fluid Mechanics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a rectangular channel, the ratio of the velocity head to the flow depth for critical flow condition is |
| A. | \(\frac{2}{3}\) |
| B. | 2 |
| C. | \(\frac{1}{2}\) |
| D. | \(\frac{3}{2}\) |
| Answer» D. \(\frac{3}{2}\) | |
| 2. |
In a rectangular open channel, 2.0 m wide, water flows at a depth of 0.8 m. It discharges over an aerated sharp-crested weir over the full width, with depth over weir crest being 0.25 m. Cc.= 0.61. Adjusting for velocity head of approach, what would be the discharge through the channel? √2g = 4.43 units |
| A. | 0.439 m3/sec |
| B. | 0.445 m3/sec |
| C. | 0.453 m3/sec |
| D. | 0-461 m3/sec |
| Answer» D. 0-461 m3/sec | |
| 3. |
Hydraulically, the economical section of drains for large flow is: |
| A. | V-shaped |
| B. | Rectangular |
| C. | Oval shaped |
| D. | Circular |
| Answer» E. | |
| 4. |
Discharge over Cipolletti weir of length 200 cm for a head over the weir of 100 cm in m3/s is: |
| A. | 0.366 |
| B. | 36.6 |
| C. | 0.00366 |
| D. | 3.66 |
| Answer» E. | |
| 5. |
Consider the following statements with respect to weir under discussion:1. Its design corresponds to soft sandy foundation.2. The difference in weir crest and downstream river bed may not exceed3. When water passes over it, the longitudinal location of the formation of a hydraulic jump is variable.This weir is of the type |
| A. | Vertical drop weir |
| B. | Masonry or concrete sloping weir |
| C. | Dry stone slope weir |
| D. | Parabolic weir |
| Answer» C. Dry stone slope weir | |
| 6. |
In a 90° triangular notch, in the error in the estimated discharge for a given head due to an error of 1% in cutting the vertex angle is |
| A. | zero |
| B. | 1% |
| C. | \( {\pi \over 2}\)% |
| D. | π % |
| Answer» D. π % | |
| 7. |
At a hydraulic jump, the depths at its two sides are 0.3 m and 1.2 m. The head loss in the jump is |
| A. | 1.0 m |
| B. | 0.8 m |
| C. | 0.5 m |
| D. | 0.45 m |
| Answer» D. 0.45 m | |
| 8. |
In a rectangular channel, carrying a certain discharge at a depth Y0 and Froude number \(F_{0'}\:then\:\dfrac{Y_c}{Y_0}=\) |
| A. | F0 |
| B. | \(F_0^{1/2}\) |
| C. | \(F_0^{3/2}\) |
| D. | \(F_0^{2/3}\) |
| Answer» E. | |
| 9. |
For best hydraulic rectangular cross - section of an open channel, its depth should be equal to |
| A. | width |
| B. | two times the width |
| C. | half of the width |
| D. | three - eighth of the width |
| Answer» D. three - eighth of the width | |
| 10. |
A hydraulic jump takes place in a frictionless rectangular channel. The pre-jump depth is yp. The alternate and sequent depths corresponding to yp are ya and ys respectively. The correct relationship among yp, ya and ys is: |
| A. | \({y_a} < {y_s} < {y_p}\) |
| B. | \({y_p} < {y_s} < {y_a}\) |
| C. | \({y_p} < {y_s} = {y_a}\) |
| D. | \({y_p} = {y_s} = {y_a}\) |
| Answer» C. \({y_p} < {y_s} = {y_a}\) | |
| 11. |
Hydraulic jump forms in a horizontal rectangular channel carrying a unit discharge of 1.019 m3/sec/m at a depth of 101.9 mm. This jump is classified as |
| A. | Weak jump |
| B. | Oscillating jump |
| C. | Steady jump |
| D. | Strong jump |
| Answer» E. | |
| 12. |
A trapezoidal channel with bed width of 2 m and side slopes of 2V on 1H, critical flow occurs at a depth of 1 m. What will be the quantity of flow and flow velocity? |
| A. | 2.86 m/sec and 6.15 m3/sec |
| B. | 1.86 m/sec and 6.15 m3/sec |
| C. | 2.86 m/sec and 7.15 m3/sec |
| D. | 3.86 m/sec and 7.15 m3/sec |
| Answer» D. 3.86 m/sec and 7.15 m3/sec | |
| 13. |
A rectangular channel will be most economical when the flow depth to bottom width are in the ratio |
| A. | 1 : 4 |
| B. | 1 : 2 |
| C. | 1 : 1 |
| D. | 2 : 1 |
| Answer» C. 1 : 1 | |
| 14. |
An open channel is of isosceles triangle shape, with side slopes 1 vertical and n horizontal. The ratio of the critical depth to specific energy at critical depth will be |
| A. | 2/3 |
| B. | 3/4 |
| C. | 4/5 |
| D. | 5/6 |
| Answer» D. 5/6 | |
| 15. |
A partially open sluice gate discharges water at 6 m/s with a depth of 40 cm in a rectangular horizontal channel of width 5 m. What would be the post-jump depth of flow on the downstream of the gate by taking g as 10 m/s2? |
| A. | 1.51 m |
| B. | 1.70 m |
| C. | 1.85 m |
| D. | 1.95 m |
| Answer» B. 1.70 m | |
| 16. |
For most economical section using Chezy’s formula, depth of flow for maximum discharge through circular channel of diameter d is: |
| A. | 0.5D |
| B. | D |
| C. | 0.95D |
| D. | 0.3D |
| Answer» D. 0.3D | |
| 17. |
If head over the rectangular notch is H, volume flow rate is Q, coefficient of discharge is Cd, then length of the notch is given by |
| A. | \(\frac{Q}{{{C_d}\sqrt {2g} \;{H^{3/2}}}}\) |
| B. | \(\frac{{3Q}}{{2{C_d}\sqrt {2g} \;{H^{3/2}}}}\) |
| C. | \(\frac{Q}{{{C_d}\sqrt {2g} \;{H^{5/2}}}}\) |
| D. | \(\frac{{3Q}}{{2{C_d}\sqrt {2g} {H^{5/2}}}}\) |
| Answer» C. \(\frac{Q}{{{C_d}\sqrt {2g} \;{H^{5/2}}}}\) | |
| 18. |
In a venturiflume, the flow takes place at |
| A. | atmospheric pressure |
| B. | gauge pressure |
| C. | absolute pressure |
| D. | none of these |
| Answer» B. gauge pressure | |
| 19. |
Consider the occurrence of a surge at the water surface of a wide rectangular channel flow, as in the figure. where the one-dimensionally considered velocities are v1, and v2 and the depths are d1and d2, with the surge height h, whereby d2 - d1 = h, moving at a speed of VW. over depth d1. Joint application of continuity and momentum principles will indicate the surge front speed VW, to be |
| A. | \({{\rm{V}}_w} = \sqrt {g{d_1}} \;{\left( {1\frac{3}{2}\frac{h}{{{d_1}}}} \right)^{1/2}}\) |
| B. | \({{\rm{V}}_w} = \sqrt {g{d_1}} \;{\left( {1 + \frac{3}{2}\frac{h}{{{d_1}}} + \frac{1}{2}{{\left( {\frac{h}{{{d_1}}}} \right)}^2}} \right)^{1/2}}\) |
| C. | \({{\rm{V}}_w} = \sqrt {g{d_1}} \;{\left( {1 + \frac{h}{{{d_1}}}} \right)^{1/2}}\) |
| D. | \({{\rm{V}}_w} = \sqrt {g{d_1}} \;{(1 + \frac{h}{{{d_1}}})^2}^{1/2}\) |
| Answer» C. \({{\rm{V}}_w} = \sqrt {g{d_1}} \;{\left( {1 + \frac{h}{{{d_1}}}} \right)^{1/2}}\) | |
| 20. |
In a hydraulic jump, the depths on the two sides are 0.4 in and 1.4 m. The head loss in the jump is nearly |
| A. | 0.45 m |
| B. | 0.65 m |
| C. | 0.80 m |
| D. | 0.90 m |
| Answer» B. 0.65 m | |
| 21. |
In a 5 m wide rectangular channel, the velocity u distribution in the vertical direction y is given by \(u=1.25~{{y}^{\frac{1}{6}}}.\) The distance y is measured from the channel bed. If the flow depth is 2 m, the discharge per unit width of the channel is |
| A. | 2.40 m3/s/m |
| B. | 2.80 m3/s/m |
| C. | 3.27 m3/s/m |
| D. | 12.02 m3/s/m |
| Answer» B. 2.80 m3/s/m | |
| 22. |
For obtaining the most economical trapezoidal channel section with depth of flow = 3 m, what is the hydraulic mean radius ? |
| A. | 1.5 m |
| B. | 3.0 m |
| C. | 2.0 m |
| D. | 1.0 m |
| Answer» B. 3.0 m | |
| 23. |
A rectangular channel of 2.5 m width is carrying a discharge of 4 m3/s. Considering that acceleration due to gravity as 9.81 m/s2, the velocity of flow (in m/s) corresponding to the critical depth (at which the specific energy is minimum) is _______ |
| A. | 1.5 |
| B. | 0.5 |
| C. | 2.5 |
| D. | 1 |
| Answer» D. 1 | |
| 24. |
If the Froude number in open channel flow is equal to 1.0, the flow is called |
| A. | streaming flow |
| B. | tranquil flow |
| C. | shooting flow |
| D. | critical flow |
| Answer» E. | |
| 25. |
For which angle of triangular notch the discharge over it is maximum? |
| A. | 30° |
| B. | 45° |
| C. | 60° |
| D. | 90° |
| Answer» E. | |
| 26. |
If H1 is the height of the liquid surface above the orifice top, H2 is the height of the liquid surface above the orifice bottom, b is the width of the orifice and Cd is the coefficient of discharge, what would be the expression to calculate the discharge denoted by Q? |
| A. | \(Q = \frac{1}{2} \times 3{C_d}b\sqrt {2g} (H_2^{3/2} - H_1^{3/2})\) |
| B. | \(Q = \frac{1}{2} \times 3{C_d}b\sqrt {2g} (H_1^{3/2} - H_2^{3/2})\) |
| C. | \(Q = \frac{1}{3} \times 2{C_d}b\sqrt {2g} (H_1^{3/2} - H_2^{3/2})\) |
| D. | \(Q = \frac{1}{3} \times 2{C_d}b\sqrt {2g} (H_2^{3/2} - H_1^{3/2})\) |
| Answer» E. | |
| 27. |
For a hydraulically efficient rectangular channel of bed width 5 m, the hydraulic radius is equal to |
| A. | 1.25 m |
| B. | 2 m |
| C. | 2.25 m |
| D. | 1.75 m |
| Answer» B. 2 m | |
| 28. |
A trapezoidal channel has a bottom width of 6 m and a side slope of 1:1. The depth of flow is 2 m at a discharge of 24 m3 /s. What would be the specific energy (take, g = 10 m/s2 )? |
| A. | 2.61 m |
| B. | 1.00 m |
| C. | 2.91 m |
| D. | 2.11 m |
| Answer» E. | |
| 29. |
At a hydraulic jump, the depths at the two sides are 0.3 and 1.4 m. The head loss in the jump is nearly |
| A. | 1.0 m |
| B. | 0.95 m |
| C. | 0.79 m |
| D. | 0.45 m |
| Answer» D. 0.45 m | |
| 30. |
At a hydraulic jump, the flow depths are 0.4 m and 5 m at the upstream and downstream, respectively. The channel is wide rectangular. The discharge per unit width is nearly |
| A. | 5.8 m2/s |
| B. | 6.4 m2/s |
| C. | 7.3 m2/s |
| D. | 8.3 m2/s |
| Answer» D. 8.3 m2/s | |
| 31. |
A hydraulic jump ensures |
| A. | Change of subcritical flow to supercritical flow |
| B. | Change of supercritical flow to subcritical flow |
| C. | Change of subcritical flow to critical flow |
| D. | Change of supercritical flow to critical flow |
| E. | No chnge |
| Answer» C. Change of subcritical flow to critical flow | |
| 32. |
For maximum discharge over a triangular notch, the angle of the notch should be: |
| A. | 30° |
| B. | 60° |
| C. | 90° |
| D. | 120° |
| Answer» D. 120° | |
| 33. |
A rectangular open channel of 6 m width is carrying a discharge of 20 m3/s. Consider the acceleration due to gravity as 9.81 m/s2 and assume water as incompressible and inviscid. The depth of flow in the channel at which the specific energy of the flowing water is minimum for the given discharge will then be: |
| A. | 3.18 m |
| B. | 1.04 m |
| C. | 0.82 m |
| D. | 2.56 m |
| Answer» C. 0.82 m | |
| 34. |
A 4 m wide rectangular channel, having bed slope of 0.001 carries a discharge of 16 m3/s.Considering Manning's roughness coefficient = 0.012 and g = 10 m/s2, the category of the channel slope is: |
| A. | Horizontal |
| B. | Mild |
| C. | Critical |
| D. | Steep |
| Answer» C. Critical | |
| 35. |
A hydraulic jump is formed when |
| A. | a subcritical flow meets a supercritical flow. |
| B. | a subcritical flow meets a subcritical flow. |
| C. | a supercritical flow meets a supercritical flow. |
| D. | a supercritical flow meets a subcritical flow. |
| Answer» E. | |
| 36. |
A rectangular open channel has a width of 5m and a bed slope of 0.001. For a uniform flow of depth 2m, the velocity is 2m/s. The Manning’s roughness coefficient for the channel is |
| A. | 0.017 |
| B. | 0.050 |
| C. | 0.033 |
| D. | 0.002 |
| Answer» B. 0.050 | |
| 37. |
A 7.5 m wide rectangular channel conveys 12 m3/s of water with a velocity of 1.5 m/s. The specific energy head of the flow is |
| A. | 1.18 m |
| B. | 1.78 m |
| C. | 2.18 m |
| D. | 2.78 m |
| Answer» B. 1.78 m | |
| 38. |
Development of surges in open channel is |
| A. | Gradually varied flow |
| B. | rapidly varied flow |
| C. | steady flow |
| D. | normal flow |
| Answer» C. steady flow | |
| 39. |
A circular pipe has a diameter of 1 m, bed slope of 1 in 1000, and Manning’s roughness coefficient equal to 0.01. It may be treated as an open channel flow when it is flowing just full, i.e., the water level just touches the crest. The discharge in this condition is denoted by Qfull. Similarly, the discharge when the pipe is flowing half-full, i.e., with a flow depth of 0.5 m, is denoted by Qhalf. The ratio Qfull/Qhalf is: |
| A. | 1 |
| B. | \(\sqrt 2 \) |
| C. | 2 |
| D. | 4 |
| Answer» D. 4 | |
| 40. |
A 1m wide rectangular channel has a bed slope of 0.0016 and the Manning’s roughness coefficient is 0.04. Uniform flow takes place in the channel at a flow depth of 0.5. At a particular section gradually varied flow GVF is observed and the flow depth is measured as 0.6m. The GVF profile at that section is classified as |
| A. | S1 |
| B. | S2 |
| C. | M1 |
| D. | M2 |
| Answer» D. M2 | |
| 41. |
In a wide rectangular channel, the normal depth is increased by 20%. This would mean an increase in the discharge of the channel nearly by |
| A. | 20% |
| B. | 26% |
| C. | 36% |
| D. | 56% |
| Answer» D. 56% | |
| 42. |
For a hydraulically efficient rectangular channel of bed width 5 m, the hydraulic radius is |
| A. | 0.5 m |
| B. | 1.25 m |
| C. | 2.75 m |
| D. | 4.25 m |
| Answer» C. 2.75 m | |
| 43. |
In a suppressed rectangular weir, the calculated discharge was found to be 3% in excess of the actual discharge. If this discrepancy was due to an error in reading the head, the measured head was: |
| A. | 3% excess |
| B. | 2% less |
| C. | 2% excess |
| D. | 1.5% excess |
| Answer» D. 1.5% excess | |
| 44. |
M3 Profile is indicated by which of the following conditions? |
| A. | y0 > yc > y |
| B. | y> y0> yc |
| C. | yc > yo> y |
| D. | y > yc> yo |
| Answer» B. y> y0> yc | |
| 45. |
A rectangular channel section is most economical when the depth of flow and bottom width is in the ratio of ____________. |
| A. | 2 : 1 |
| B. | 1 : 1 |
| C. | 1 : 2 |
| D. | 1 : 4 |
| Answer» D. 1 : 4 | |
| 46. |
Discharge (Q) over a triangular notch or weir is given by - |
| A. | \({c_d}\sqrt {2g} \tan \frac{\theta }{2} \cdot {H^{\frac{5}{2}}}\) |
| B. | \(\frac{1}{2}{c_d}\sqrt {2g} \tan \frac{\theta }{2} \cdot {H^{\frac{5}{2}}}\) |
| C. | \(\frac{8}{15}{c_d}\sqrt {2g} \tan \frac{\theta }{2} \cdot {H^{\frac{5}{2}}}\) |
| D. | \(\frac{2}{3}{c_d}\sqrt {2g} \tan \frac{\theta }{2} \cdot {H^{\frac{5}{2}}}\) |
| Answer» D. \(\frac{2}{3}{c_d}\sqrt {2g} \tan \frac{\theta }{2} \cdot {H^{\frac{5}{2}}}\) | |
| 47. |
For a given discharge in an open channel, there are two depths which have the same specific energy. These two depths are known as |
| A. | alternate depths |
| B. | critical depths |
| C. | normal depths |
| D. | sequent depths |
| Answer» B. critical depths | |
| 48. |
Consider the following statements regarding a gradually varied flow in a prismatic open channel:1. Total energy line remains parallel to the water surface.2. The rate of energy loss at the section is inversely proportional to dX where d is flow depth with index x.3. In analysing the flow, the energy equation of flow is not applicable.4. Pressure distribution at every section can be assumed to be hydrostatic.Which of the above statements are correct? |
| A. | 1 and 4 |
| B. | 2 and 4 |
| C. | 1 and 2 |
| D. | 2 and 3 |
| Answer» C. 1 and 2 | |