MCQOPTIONS
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MCQOPTIONS
This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Thermal Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following statements regarding a Reaction turbine is FLASE? |
| A. | The relative velocity of steam with respect to moving blade increases as the steam glides over the turbine blade |
| B. | The degree of reaction for a reaction turbine is defined as the ratio of heat drop in moving blade to heat drop in the stage |
| C. | If the degree of reaction of a reaction turbine is 50% then, the moving blade and the fixed blades have the same shape |
| D. | The angles of receiving tips of fixed and moving blades are always equal |
| Answer» E. | |
| 2. |
Which of the following is the correct definition of Shaft Power ? |
| A. | It is the power developed by the blades |
| B. | It is the power developed at the rim |
| C. | It is the power based on the total internal steam flow and adiabatic heat drop |
| D. | It is the actual power transmitted by the turbine |
| Answer» E. | |
| 3. |
Which of the following is the correct definition for Adiabatic Power ? |
| A. | It is the power developed at the rim |
| B. | It is the actual power transmitted by the turbine |
| C. | It is the power based on the total internal steam flow and adiabatic heat drop |
| D. | It is the power developed by the blades |
| Answer» D. It is the power developed by the blades | |
| 4. |
Which of the following is the correct expression for net efficiency in steam turbines? |
| A. | ( frac{Brake , thermal , efficiency}{Thermal , efficiency , on , the , Rankine , cycle} ) |
| B. | ( frac{Brake , thermal , efficiency}{Thermal , efficiency , on , the , Carnot , cycle} ) |
| C. | ( frac{Thermal , efficiency , on , the , Rankine , cycle}{Brake , thermal , efficiency} ) |
| D. | ( frac{Thermal , efficiency , on , the , Carnot , cycle}{Brake , thermal , efficiency} ) |
| Answer» B. ( frac{Brake , thermal , efficiency}{Thermal , efficiency , on , the , Carnot , cycle} ) | |
| 5. |
Which of the following is the correct formula for overall turbine efficiency in steam turbines? |
| A. | ( frac{Work , delivered , at , the , turbine , cooupling , in , heat , units , per , kg , of vsteam}{Total , adiabatic , heat , drop} ) |
| B. | ( frac{Work delivered , at , the , turbine , cooupling , in , heat , units , per , kg , of , steam}{Adiabatic , heat , drop , per , stage} ) |
| C. | ( frac{Thermal , efficiency , on , a , Rankine , cycle}{Brake , thernal , efficieny} ) |
| D. | ( frac{Heat , converted , into , useful , work}{Adiabatic , heat , drop , per , stage} ) |
| Answer» B. ( frac{Work delivered , at , the , turbine , cooupling , in , heat , units , per , kg , of , steam}{Adiabatic , heat , drop , per , stage} ) | |
| 6. |
Which of the following is the correct expression for internal efficiency in steam turbines? |
| A. | ( frac{Heat , converted , into , useful , work}{Total , adiabatic , heat , drop} ) |
| B. | ( frac{Net , work , done , on , shaft , per , stage , per , kg , of , steam}{Adiabatic , heat , drop , per , stage} ) |
| C. | |
| D. | ( frac{Net , work , done , on , shaft , per , stage , per , kg , of , steam}{Total , adiabatic , heat , drop} ) |
| E. | ( frac{Heat , converted , into , useful , work}{Net , work , done , on , shaft , per , stage , per , kg , of , steam} ) |
| Answer» B. ( frac{Net , work , done , on , shaft , per , stage , per , kg , of , steam}{Adiabatic , heat , drop , per , stage} ) | |
| 7. |
Which of the following is the correct expression to calculate stage efficiency in steam turbines? |
| A. | ( frac{Heat , converted , into , useful , work}{Adiabatic , heat , drop , per , stage} ) |
| B. | ( frac{Net , work , done , on , shaft , per , stage , per , kg , of , steam}{Adiabatic , heat , drop , per , stage} ) |
| C. | ( frac{Heat , converted , into , useful , work}{Total , adiabatic , heat , drop} ) |
| D. | ( frac{Net , work , done , on , shaft , per , stage , per , kg , of , steam}{Total , adiabatic , heat , drop} ) |
| Answer» C. ( frac{Heat , converted , into , useful , work}{Total , adiabatic , heat , drop} ) | |
| 8. |
In a steam turbine the turbine blade s tip experiences more erosion than any other part. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 9. |
A 50% reaction turbine, having symmetrical velocity triangles, runs at 1500 r.p.m. The exit angles of the blades are 20 . The speed ratio is 0.8 and the diameter of the rotor blades is 1 meter. Determine the power developed if the mass flow rate of steam is 0.785 kg per second. |
| A. | 6.534 kW |
| B. | 7.654 kW |
| C. | 8.425 kW |
| D. | 9.612 kW |
| Answer» B. 7.654 kW | |
| 10. |
In a reaction turbine, the fixed blades and moving blades are of the same shape but reversed in direction. The angle of the discharging tip is 20 . The mean blade velocity is 200 m/s. The axial velocity of flow of steam is half of the mean blade velocity. Determine the inlet angles of blades. |
| A. | 45 |
| B. | 53 |
| C. | 63 |
| D. | 71 |
| Answer» C. 63 | |
| 11. |
The efficiency of steam turbine is greater than that of gas turbines. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 12. |
The nozzle angle of a Parson s reaction turbine is 25 . Determine the maximum possible efficiency for the turbine. |
| A. | 75.62% |
| B. | 84.56% |
| C. | 90.19% |
| D. | 93.21% |
| Answer» D. 93.21% | |
| 13. |
Calculate the mean blade velocity of a Parson s reaction turbine, if the steam leaves the nozzle with an absolute velocity of 320 m/s. Take the nozzle angle as 20 and the turbine works at maximum efficiency. |
| A. | 156 m/s |
| B. | 189 m/s |
| C. | 256 m/s |
| D. | 301 m/s |
| Answer» E. | |
| 14. |
Which of the following graphs shows correct variation of efficiency of a Parson s reaction turbine with respect to blade speed ratio? |
| A. | <img alt="Variation of efficiency of Parsons reaction turbine w.r.t blade speed ratio - option a" class="alignnone size-full wp-image-286430" height="205" sizes="(max-width: 308px) 100vw, 308px" src="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1a.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1a.png 308w, https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1a-300x200.png 300w" width="308"/> |
| B. | <img alt="Variation of efficiency of Parsons reaction turbine w.r.t blade speed ratio - option b" class="alignnone size-full wp-image-286429" height="241" src="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1b.png" width="288"/> |
| C. | <img alt="Variation of efficiency of Parsons reaction turbine w.r.t blade speed ratio - option c" class="alignnone size-full wp-image-286428" height="200" src="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1c.png" width="256"/> |
| D. | <img alt="Variation of efficiency of Parsons reaction turbine w.r.t blade speed ratio - option d" class="alignnone size-full wp-image-286427" height="203" src="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1d.png" width="235"/> |
| Answer» C. <img alt="Variation of efficiency of Parsons reaction turbine w.r.t blade speed ratio - option c" class="alignnone size-full wp-image-286428" height="200" src="https://www.sanfoundry.com/wp-content/uploads/2020/08/thermal-engineering-multiple-choice-questions-answers-q1c.png" width="256"/> | |