MCQOPTIONS
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MCQOPTIONS
This section includes 36 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 most of the economical rectangular sections of a channel, depth is kept equal to: |
| A. | One-fourth of the width |
| B. | Three times the hydraulic radius |
| C. | Half the width |
| D. | Hydraulic mean depth |
| Answer» D. Hydraulic mean depth | |
| 2. |
A trapezoidal channel has a bottom width of 6 m and side slope of 1 : 1. The depth of flow is 1.5 m at a discharge of 15 cum/sec. The hydraulic radius and hydraulic average depth of flow respectively are |
| A. | 1.098 m, 1.25 m |
| B. | 2.239 m, 2.50 m |
| C. | 1.25 m, 1.098 m |
| D. | 2.50 m, 2.239 m |
| Answer» B. 2.239 m, 2.50 m | |
| 3. |
Depth at which specific energy is minimum is known as |
| A. | Critical depth |
| B. | Conjugate depth |
| C. | Alternate depth |
| D. | Normal depth |
| Answer» B. Conjugate depth | |
| 4. |
Chezy’s equation is used to determine |
| A. | velocity of flow in open channel |
| B. | velocity of flow in pipe |
| C. | flow over weirs |
| D. | discharge through notch |
| Answer» B. velocity of flow in pipe | |
| 5. |
In case of depressed nappe the pressure of air below the nappe is |
| A. | less than atmospheric |
| B. | more than atmospheric |
| C. | equal to atmospheric |
| D. | None of these |
| Answer» B. more than atmospheric | |
| 6. |
A bridge has a linear waterway of 150 meters constructed across a stream whose natural linear waterway is 200 meters. If the average flood depth is 3 meters and average flood discharge is 1200 m3/sec, the velocity of approach is |
| A. | 2.0 m/sec |
| B. | 2.66 m/sec |
| C. | 6.0 m/sec |
| D. | 8.0 m/sec |
| Answer» B. 2.66 m/sec | |
| 7. |
In a hydraulic jump, if the Froude number F1 = 4.5 to 9.0, then the jump is called a/an: |
| A. | steady jump |
| B. | undular jump |
| C. | oscillating jump |
| D. | weak jump |
| Answer» B. undular jump | |
| 8. |
In an open channel flow, the ratio of wetted area to wetted perimeter of the cross section is: |
| A. | Section factor |
| B. | Hydraulic radius |
| C. | Hydraulic depth |
| D. | Hydraulic exponent |
| Answer» C. Hydraulic depth | |
| 9. |
How the best hydraulic channel cross-section is defined? |
| A. | The section with minimum roughness coefficient |
| B. | The section that has a maximum area for a given flow |
| C. | The section that has a minimum wetted perimeter |
| D. | The section that has a maximum wetted area |
| Answer» D. The section that has a maximum wetted area | |
| 10. |
A trapezoidal channel with base of 6 m and side slope of two horizontal to one vertical conveys water at 17 m3/sec with a depth of 1.5 m. The flow situation in the channel is: |
| A. | Critical |
| B. | Supercritical |
| C. | Subcritical |
| D. | None of the above |
| Answer» D. None of the above | |
| 11. |
In an open channel, a moving wave front which brings about an abrupt change in depth of flow is known as __________. |
| A. | tranquil flow |
| B. | steady flow |
| C. | sutro |
| D. | surge |
| Answer» E. | |
| 12. |
Hydraulic Gradient Line represents the sum of |
| A. | Pressure Head and kinetic Head |
| B. | Kinetic Head and Elevation Head |
| C. | Pressure Head, Kinetic Head and Elevation Head |
| D. | Pressure Head and Elevation Head |
| Answer» E. | |
| 13. |
In a trapezoidal channel section, what is the condition to keep the depth of flow constant? |
| A. | Z = 1 and θ =30° |
| B. | \(Z =\sqrt{3} \) and θ = 90° |
| C. | Z = \(1/\sqrt{3}\) and θ = 60° |
| D. | Z = 1 and θ = 30° |
| Answer» D. Z = 1 and θ = 30° | |
| 14. |
A triangular open channel has a vortex angle of 90° and carries flow at a critical depth of 0.3 m. The discharge in the channel is |
| A. | 0.41 m3 / s |
| B. | 0.11 m3 / s |
| C. | 0.21 m3 / s |
| D. | 0.31 m3 / s |
| Answer» C. 0.21 m3 / s | |
| 15. |
A weir system in which the downstream water level of the weir nappe is higher than the crest is called _____. |
| A. | Submerged |
| B. | Overflowing |
| C. | Broad-crested |
| D. | Cipoletti |
| Answer» B. Overflowing | |
| 16. |
Notch is a device used for measuring: |
| A. | Velocity through small channels |
| B. | Rate of flow through pipes |
| C. | Rate of flow through a small channels |
| D. | Velocity through pipes |
| Answer» D. Velocity through pipes | |
| 17. |
Critical-depth meter is used to measure _____. |
| A. | Discharge in an open channel |
| B. | Hydraulic jump |
| C. | Depth of flow in channel |
| D. | Depth of channel |
| Answer» B. Hydraulic jump | |
| 18. |
Consider a wide rigid-boundary canal with bed slope of 0.004, Manning’s n = 0.18, and depth of flow = 0.88 m. The average boundary shear stress will be |
| A. | 17.2 × 106 N / mm2 |
| B. | 18.2 × 106 N / mm2 |
| C. | 19.2 × 106 N / mm2 |
| D. | 34.5 × 106 N / mm2 |
| Answer» E. | |
| 19. |
Find the discharge of water through the channel shown in figure. Assume velocity of water is 1.25 m/s. |
| A. | 2.5 m3/s |
| B. | 1.606 m3/s |
| C. | 0.805 m3/s |
| D. | 3.420 m3/s |
| Answer» C. 0.805 m3/s | |
| 20. |
For the same specific force, the two depths at which a given discharge can occur are called: |
| A. | Alternate depths |
| B. | Normal depths |
| C. | Sequent depths |
| D. | Critical depths |
| Answer» D. Critical depths | |
| 21. |
A 1.2 m wide rectangular channel of bed slope 0.0004 and manning’s coefficient 0.01, carrying the discharge of 0.5 m3/s. The normal depth of the channel is_______. |
| A. | 0.13 |
| B. | 0.32 |
| C. | 0.43 |
| D. | 0.5 |
| Answer» E. | |
| 22. |
If water is flowing at the same depth in most hydraulically efficient triangular and rectangular channel sections then the ratio of hydraulic radius of triangular section to that of rectangular section is |
| A. | 2 |
| B. | \(\sqrt{2}\) |
| C. | 1 |
| D. | \(\frac{1}{\sqrt{2}}\) |
| Answer» E. | |
| 23. |
In a horizontal rectangular channel, if the Froude number of an incoming supercritical flow is 6, then the jump so formed will be |
| A. | Undular |
| B. | Weak |
| C. | Steady |
| D. | Oscillating |
| E. | Strong |
| Answer» D. Oscillating | |
| 24. |
In the most efficient rectangular channel section, hydraulic radius is equal to _________. |
| A. | full of depth of flow |
| B. | none of the above |
| C. | quarter of depth of flow |
| D. | half of depth of flow |
| Answer» E. | |
| 25. |
Calculate the approximate specific energy of a trapezoidal channel having a bottom width of 6 metres, ratio of side slopes is 1: 1 and the depth of flow at a discharge speed of 15 cubic metres per second is 1.5 metres. |
| A. | 2.6 |
| B. | 1.6 |
| C. | 3.6 |
| D. | 4.6 |
| Answer» C. 3.6 | |
| 26. |
In the step methods (both direct and standard), the computations must _____ |
| A. | proceed downstream in subcritical flow |
| B. | proceed upstream in subcritical flow |
| C. | always proceed upstream |
| D. | None of these |
| Answer» C. always proceed upstream | |
| 27. |
Hydraulic diameter used in place of diameter of non-circular ducts is equal to |
| A. | A/m |
| B. | (4A)/m |
| C. | A/(4m) |
| D. | m/A |
| Answer» C. A/(4m) | |
| 28. |
For a pipe of diameter 1 m when running full, the hydraulic mean depth will be: |
| A. | 0.75 m |
| B. | 1.0 m |
| C. | 0.5 m |
| D. | 0.25 m |
| Answer» E. | |
| 29. |
Field observations are carried out to assess the discharge of a river. Measurements are taken in a 2000 m straight reach. Slope is approximately 1 in 4000. Bed slope is determinably to a possible accuracy of 0.4 cm; wetted perimeter is determinable within 4% of possible error; and sectional area within 6% of possible error. Using Chezy’s equation, the assessed discharge will be accurate to within |
| A. | 9.6% |
| B. | 10.8% |
| C. | 11.4% |
| D. | 12.7% |
| Answer» D. 12.7% | |
| 30. |
If the Froude number of a hydraulic jump in a horizontal rectangular channel is 4.2, then the jump can be classified as: |
| A. | Undular jump |
| B. | Oscillating jump |
| C. | Weak jump |
| D. | Steady jump |
| Answer» C. Weak jump | |
| 31. |
In the design of spillway when He = Hd, the value of ‘C’ is |
| A. | 1.00 |
| B. | 1.33 |
| C. | 2.00 |
| D. | 2.20 |
| Answer» E. | |
| 32. |
In an open channel flow, for best efficiency of a rectangular section channel, ratio of bottom width to depth shall be: |
| A. | 1 |
| B. | \(\dfrac{1}{2}\) |
| C. | \(\dfrac{1}{4}\) |
| D. | 2 |
| Answer» E. | |
| 33. |
Consider the given statements with respect to most economic sections of a rectangular channel and select the correct option.A. Discharge shall be maximumB. Wetted perimeter shall be minimum |
| A. | Both the statements are true |
| B. | Statement A is false and statement B is true |
| C. | Statement A is true and statement B is flase |
| D. | Both the statements are false |
| Answer» B. Statement A is false and statement B is true | |
| 34. |
If the Froude number of a hydraulic jump is 2.0, the jump can be classified as: |
| A. | Undular jump |
| B. | Weak Jump |
| C. | Oscillating jump |
| D. | Steady jump |
| Answer» C. Oscillating jump | |
| 35. |
For an accurate flow measurement in open channel, an arrangement for aeration under the nappe is necessary when the weir used is: |
| A. | Contracted rectangular |
| B. | Triangular |
| C. | Submerged contracted rectangular |
| D. | Suppressed rectangular |
| Answer» E. | |
| 36. |
In a rectangular channel section, if the critical depth is 2.0 m, the specific energy at critical depth is |
| A. | 3.0 m |
| B. | 1.33 m |
| C. | 2.5 m |
| D. | 1.5 m |
| Answer» B. 1.33 m | |