McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Civil Engineering .
Chapters
| 701. |
What is the water flow direction in the runner in a Francis turbine? |
| A. | Axial and then tangential |
| B. | Tangential and then axial |
| C. | Radial and then axial |
| D. | Axial and then radial |
| Answer» C. Radial and then axial | |
| 702. |
Which of the following is true in case of flow of water before it enters the runner of a Francis Turbine? |
| A. | Available head is entirely converted to velocity head |
| B. | Available head is entire converted to pressure head |
| C. | Available head is neither converted to pressure head nor velocity head |
| D. | Available head is partly converted to pressure head and partly to velocity head |
| Answer» D. Available head is partly converted to pressure head and partly to velocity head | |
| 703. |
Why does the cross sectional area of the Spiral casing gradually decrease along the circumference of the Francis turbine from the entrance to the tip? |
| A. | To ensure constant velocity of water during runner entry |
| B. | To prevent loss of efficiency of the turbine due to impulsive forces caused by extra area |
| C. | To prevent leakage from the turbine |
| D. | To reduce material costs in order to make the turbine more economical |
| Answer» A. To ensure constant velocity of water during runner entry | |
| 704. |
Which of the following profiles are used for guide vanes to ensure smooth flow without separation? |
| A. | Rectangular |
| B. | Bent Rectangular |
| C. | Elliptical |
| D. | Aerofoil |
| Answer» D. Aerofoil | |
| 705. |
In which of the following type of runners the velocity of whirl at inlet is greater than the blade velocity? |
| A. | Such a case is practically impossible |
| B. | Slow Runner |
| C. | Medium Runner |
| D. | Fast Runner |
| Answer» B. Slow Runner | |
| 706. |
Which of the following runner types will have the highest vane angle at inlet (β1 value)? |
| A. | Slow Runner |
| B. | Medium Runner |
| C. | Fast Runner |
| D. | Vane angle is defined only for Kaplan Turbines and not Francis turbines |
| Answer» C. Fast Runner | |
| 707. |
In case of a Medium runner, tan (α1) CANNOT be given by (α1 = Guide vane angle at inlet)? |
| A. | Vf1 / Vw1 |
| B. | Vr1 / Vw1 |
| C. | Vr1 / u1 |
| D. | Vw1 / u1 |
| Answer» D. Vw1 / u1 | |
| 708. |
In the velocity diagrams for Francis turbine, which of the following velocity directions is along the blade curvature? |
| A. | Vr1 |
| B. | Vw1 |
| C. | V1 |
| D. | u1 |
| Answer» A. Vr1 | |
| 709. |
In the figure shown below,which of the following angles replace the question mark? |
| A. | Guide vane angle at inlet |
| B. | Blade angle at inlet |
| C. | Vane angle at inlet |
| D. | Blade angle at outlet |
| Answer» A. Guide vane angle at inlet | |
| 710. |
In the figure shown below, which of the following type of runners has the blade curvature as shown in the above figure (The arrow denotes direction of blade motion)? |
| A. | Information insufficient to determine |
| B. | Slow Runner |
| C. | Medium Runner |
| D. | Fast Runner |
| Answer» B. Slow Runner | |
| 711. |
Francis turbine is typically used for which of the following values of available heads? |
| A. | 300 m |
| B. | 100 m |
| C. | 30 m |
| D. | 5 m |
| Answer» B. 100 m | |
| 712. |
Water flow velocity is given 10 m/s. The runner diameter is 3 m and the width of the wheel is 25 cm. Find the mass of water (kg) flowing across the runner per second. |
| A. | 7500π |
| B. | 50π |
| C. | 300π |
| D. | RPM of the turbine needs to be given |
| Answer» A. 7500π | |
| 713. |
Work done per second by a Francis turbine can be given by ρAVf (Vw1u1 + Vw2u2). |
| A. | True |
| B. | False |
| C. | none |
| D. | none |
| Answer» B. False | |
| 714. |
Which of the following terms is considered to be zero while deriving the equation for work done per second for Francis Turbine? |
| A. | Vr1 |
| B. | Vw2 |
| C. | Vf2 |
| D. | Vr2 |
| Answer» B. Vw2 | |
| 715. |
Power developed by Francis turbine are calculated for a certain set of conditions. Now, the inlet whirl velocity is doubled, the blade velocity at inlet is doubled and the flow velocity is quartered. The power developed: |
| A. | Is 4 times the original value |
| B. | Is 2 times the original value |
| C. | Is ½ times the original value |
| D. | Is same as the original value |
| Answer» D. Is same as the original value | |
| 716. |
Volume flow rate of water in a Francis turbine runner is 25 m3/s. The flow velocity, whirl velocity and blade velocity are 11 m/s, 10 m/s and 5 m/s respectively, all values given at runner inlet. Find the power developed by the turbine. |
| A. | 25 kW |
| B. | 1.25 MW |
| C. | 1.25 kW |
| D. | 25 MW |
| Answer» B. 1.25 MW | |
| 717. |
The flow rate of the water flow in a Francis turbine is increased by 50% keeping all the other parameters same. The work done by the turbine changes by? |
| A. | 50% increase |
| B. | 25% increase |
| C. | 100% increase |
| D. | 150% increase |
| Answer» A. 50% increase | |
| 718. |
A student performs an experiment with a Francis turbine. He accidently set the RPM of Francis turbine to 1400 rpm instead of 700 rpm. He reported the power to be 1 MW. His teacher asks him to perform the same experiment using the correct RPM. The student performs the same experiment again, but this time the erroneously doubled the flow velocity. What does the student report the power to be? |
| A. | 0.5 MW |
| B. | 0.25 MW |
| C. | 2 MW |
| D. | 1 MW |
| Answer» D. 1 MW | |
| 719. |
The available head of a Francis Turbine is 100 m. Velocity of the flow at the runner inlet is 15 m/s. Find the flow ratio. |
| A. | 0.33 |
| B. | 0.45 |
| C. | 0.67 |
| D. | 0.89 |
| Answer» A. 0.33 | |
| 720. |
How does the flow ratio (ψ) of a Francis turbine vary with available head (H)? |
| A. | ψ α H |
| B. | ψ α 1/H |
| C. | ψ α sqrt (H) |
| D. | ψ α 1/(sqrt (H)) |
| Answer» D. ψ α 1/(sqrt (H)) | |
| 721. |
What is the typical value for flow ratio in a Francis turbine? |
| A. | 0.05 – 0.1 |
| B. | 0.15 – 0.30 |
| C. | 0.35 – 0.45 |
| D. | 0.50 – 0.60 |
| Answer» B. 0.15 – 0.30 | |
| 722. |
The available head of a Francis Turbine is 120 m. The blade velocity is given 35 m/s. Find the speed ratio of the turbine. |
| A. | 0.56 |
| B. | 0.61 |
| C. | 0.71 |
| D. | 0.81 |
| Answer» C. 0.71 | |
| 723. |
The speed ratio (φ) varies directly with which of the following parameters? |
| A. | Vw1 |
| B. | V1 |
| C. | N (RPM) |
| D. | H (Available head) |
| Answer» C. N (RPM) | |
| 724. |
The typical value range of speed ratio for a Francis turbine is: |
| A. | 0.3 – 0.6 |
| B. | 0.5 – 0.6 |
| C. | 0.1 – 0.4 |
| D. | 0.6 – 0.9 |
| Answer» D. 0.6 – 0.9 | |
| 725. |
Which of the following efficiencies for Francis Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet? |
| A. | Hydraulic efficiency |
| B. | Volumetric efficiency |
| C. | Mechanical efficiency |
| D. | Overall efficiency |
| Answer» A. Hydraulic efficiency | |
| 726. |
Which of the following efficiencies for Francis Turbine is described as the ratio between total quantity of water over runner blades to total quantity of water supplied to turbine? |
| A. | Hydraulic efficiency |
| B. | Volumetric efficiency |
| C. | Mechanical efficiency |
| D. | Overall efficiency |
| Answer» B. Volumetric efficiency | |
| 727. |
Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner? |
| A. | Hydraulic efficiency |
| B. | Volumetric efficiency |
| C. | Mechanical efficiency |
| D. | Overall efficiency |
| Answer» C. Mechanical efficiency | |
| 728. |
Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet? |
| A. | Hydraulic efficiency |
| B. | Volumetric efficiency |
| C. | Mechanical efficiency |
| D. | Overall efficiency |
| Answer» D. Overall efficiency | |
| 729. |
The whirl velocity at inlet of Francis turbine is given to be 20 m/s. The blade velocity is given as 35 m/s. What is the hydraulic efficiency for a head of 100 m? |
| A. | 80% |
| B. | 90% |
| C. | 70% |
| D. | 98% |
| Answer» C. 70% | |
| 730. |
The desired hydraulic efficiency of a turbine is 80% at a whirl velocity of 20 m/s and a head of 100 m. What should be the blade velocity of the turbine at inlet in m/s? |
| A. | 40 |
| B. | 60 |
| C. | 80 |
| D. | 25 |
| Answer» A. 40 | |
| 731. |
The input water power of the Francis turbine is 1.25 times the runner power. What would be the hydraulic efficiency of the turbine (in %)? |
| A. | 60 |
| B. | 70 |
| C. | 80 |
| D. | 90 |
| Answer» C. 80 | |
| 732. |
The volume flow rate into a Francis turbine is Q m3/s. 0.25Q m3/s volume of water do not flow over the runner blades. What is the mechanical efficiency of the turbine (in %)? |
| A. | 65 |
| B. | 75 |
| C. | 80 |
| D. | Mechanical efficiency cannot be found out from the given information |
| Answer» D. Mechanical efficiency cannot be found out from the given information | |
| 733. |
The volumetric efficiency of a Francis turbine is given to be 90%. If the volume flow rate through the turbine is 25 m3/s. What is the flow rate of water over the runner blades (in m3/s)? |
| A. | 20 |
| B. | 25 |
| C. | 22.5 |
| D. | 21.5 |
| Answer» C. 22.5 | |
| 734. |
The volumetric efficiency of a given turbine is 80%. If volume flow rate of water in given to be 30 m3/s, find the volume of water (m3) NOT flowing over the runner blades per second? |
| A. | 5 |
| B. | 6 |
| C. | 10 |
| D. | 12 |
| Answer» B. 6 | |
| 735. |
The power available at the shaft of a Francis turbine is 1 MW. The volume flow rate of water in 25 m3/s, whirl velocity at inlet is 10 m/s and blade velocity is 5 m/s. Find the mechanical efficiency (in %)? |
| A. | 65 |
| B. | 75 |
| C. | 80 |
| D. | 90 |
| Answer» C. 80 | |
| 736. |
The whirl velocity at inlet is 15 m/s and blade velocity is 10 m/s. The volume flow rate of water in 20 m3/s. Find the power output available at the shaft if the mechanical efficiency is 95% (in MW)? |
| A. | 2.85 |
| B. | 3.075 |
| C. | 6.55 |
| D. | 0.285 |
| Answer» A. 2.85 | |
| 737. |
The power output of the shaft is 5 MW. The volume flow rate of water in 10 m3/s at an available head of 60 m. Find the overall efficiency of the turbine in % (g = 10 m/s2)? |
| A. | 80 |
| B. | 82.5 |
| C. | 83.3 |
| D. | 85 |
| Answer» C. 83.3 | |
| 738. |
The volume flow rate of water in 10 m3/s at an available head of 60 m (g = 10 m/s3). Find the shaft power (in MW) if the overall efficiency of the turbine is 90%. |
| A. | 54 |
| B. | 5.4 |
| C. | 540 |
| D. | 0.54 |
| Answer» B. 5.4 | |
| 739. |
The hydraulic efficiency of a Francis turbine is 90%, the mechanical efficiency is 95% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency (in %)? |
| A. | 80 |
| B. | 85.5 |
| C. | 87.5 |
| D. | 83.3 |
| Answer» B. 85.5 | |
| 740. |
In a Kaplan turbine, what is the direction of water flow? |
| A. | Axial and then axial |
| B. | Radial and then axial |
| C. | Tangential and then axial |
| D. | Tangential and then radial |
| Answer» A. Axial and then axial | |
| 741. |
For which of the following values of available heads may Kaplan turbine be used? |
| A. | 250 m |
| B. | 100 m |
| C. | 80 m |
| D. | 50 m |
| Answer» D. 50 m | |
| 742. |
In this type of low head turbine, the guide vanes are fixed to the hub of the turbine and are not adjustable. What is this type of turbine called? |
| A. | Francis turbine |
| B. | Kaplan Turbine |
| C. | Propeller Turbine |
| D. | Pelton turbine |
| Answer» A. Francis turbine | |
| 743. |
The velocity of flow through a Kaplan turbine is 10 m/s. The outer diameter of the runner is 4 m and the hub diameter is 2 m. Find the volume flow rate of the turbine in m3/s? |
| A. | 95 |
| B. | 75 |
| C. | 85 |
| D. | 105 |
| Answer» A. 95 | |
| 744. |
The velocity of the flow at the inlet of Kaplan turbine is V. In an experimental setup, what could be the possible value of the velocity of the flow at the outlet of Kaplan turbine? |
| A. | V |
| B. | 0.8V |
| C. | 1.2V |
| D. | 2V |
| Answer» B. 0.8V | |
| 745. |
Which of the following turbines will have the lowest number of blades in it? |
| A. | Pelton turbine |
| B. | Steam turbine |
| C. | Francis turbine |
| D. | Kaplan turbine |
| Answer» D. Kaplan turbine | |
| 746. |
The velocity of the flow through the Kaplan turbine is 25 m/s. The available head of the turbine is 60 m. Find the flow ratio of the turbine (take g = 10 m/s2). |
| A. | 0.65 |
| B. | 0.72 |
| C. | 0.69 |
| D. | 0.75 |
| Answer» B. 0.72 | |
| 747. |
A Kaplan turbine requires a speed ratio of 2. The available head of the turbine is 5 m. What should be the blade velocity of the turbine such that a speed ratio of 2 is maintained (take g = 10 m/s2)? |
| A. | 75.75 m/s |
| B. | 63.25 m/s |
| C. | 23.35 m/s |
| D. | 50.00 m/s |
| Answer» B. 63.25 m/s | |
| 748. |
The flow ratio of a Kaplan turbine is given as 0.7. The available head is 30 m. The outer diameter of the runner is 3.5 m and the hub diameter is 2 m. Find the volume of water flowing through the turbine per second (m3/s)? |
| A. | 90 |
| B. | 111 |
| C. | 125 |
| D. | 168 |
| Answer» B. 111 | |
| 749. |
In which of the following type of runners in a Kaplan turbine the velocity of whirl at inlet is smaller than the blade velocity? |
| A. | Such a case is practically impossible |
| B. | Slow Runner |
| C. | Medium Runner |
| D. | Fast Runner |
| Answer» D. Fast Runner | |
| 750. |
In the outlet velocity triangle of a Kaplan turbine, β2 = 30o. Vf2 = 5 m/s. What is the relative velocity of the flow at outlet? |
| A. | 10 m/s |
| B. | 5.77 m/s |
| C. | 8.66 m/s |
| D. | 2.88 m/s |
| Answer» A. 10 m/s | |
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