MCQOPTIONS
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MCQOPTIONS
This section includes 15 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. |
Find out the temperature of outside air if a chimney 30 m high creates a draught of 25 m in terms of column if hot gases. The temperature of hot gases is 330 C. 18 kg of air is to be supplied for complete combustion of 1 kg of fuel. |
| A. | 38 C |
| B. | 28 C |
| C. | 25 C |
| D. | 32 C |
| Answer» B. 28 C | |
| 2. |
How much air is used per kg of coal burnt in a boiler having a chimney of height 32 m to create draught of 170 N/m2. The temperature of outside air is 25 C and hot gases inside chimney is 330 C. |
| A. | 10.16 kg of air per kg of coal burnt |
| B. | 12.00 kg of air per kg of coal burnt |
| C. | 14.32 kg of air per kg of coal burnt |
| D. | 19.25 kg of air per kg of coal burnt |
| Answer» B. 12.00 kg of air per kg of coal burnt | |
| 3. |
A 27 m high chimney produces a draught of 30 m in terms of Column of hot gases. The amount of air supplied for complete combustion of 1 kg of fuel is 20 kg. If the temperature of outside air is 27 C, determine the temperature of the hot gases inside the chimney. |
| A. | 456 C |
| B. | 392 C |
| C. | 423 C |
| D. | 398 C |
| Answer» C. 423 C | |
| 4. |
Find draught in terms of column of hot gases, if the temperature of hot gases inside the chimney is 350 C. The height of the chimney is 30 m. The temperature of outside air is 25 C. The air supplied for complete combustion of 1 kg of fuel is 20 kg. |
| A. | 29.73 m |
| B. | 32.46 m |
| C. | 45.32 m |
| D. | 30.25 m |
| Answer» B. 32.46 m | |
| 5. |
Find the temperature of the hot gases inside the chimney if the draught produced by a 25 m high chimney is 15 mm of water. The temperature of the air outside is 25 C and 18 kg of air is supplied for complete combustion of 1 kg of fuel. |
| A. | 298 C |
| B. | 330 C |
| C. | 456 C |
| D. | 364 C |
| Answer» E. | |
| 6. |
A chimney 30 m high produces a draught of 16 mm of water. The temperature of hot gases inside the chimney is 300 C. Calculate the temperature of outside air if 20 kg of air is supplied for complete combustion of 1 kg of fuel. |
| A. | 30 C |
| B. | 27 C |
| C. | 25 C |
| D. | 20 C |
| Answer» C. 25 C | |
| 7. |
A 28 m chimney is full of hot gases at temperature 300 C. The air supplied for complete combustion of 1 kg of coal is 18 kg. calculate draught in N/m2 if the temperature of outside air is 25 C. |
| A. | 140.32 N/m<sup>2</sup> |
| B. | 187.54 N/m<sup>2</sup> |
| C. | 150.32 N/m<sup>2</sup> |
| D. | 146.76 N/m<sup>2</sup> |
| Answer» E. | |
| 8. |
Calculate how much air is used per kg of coal burnt, if the chimney height is 35 m which creates a draught of 20 mm of water. The temperature of hot gases inside the chimney is 330 C and temperature of air outside is 27 C. |
| A. | 29.52 kg of air per kg of coal |
| B. | 21.34 kg of air per kg of coal |
| C. | 22.45 kg of air per kg of coal |
| D. | 19.54 kg of air per kg of coal |
| Answer» B. 21.34 kg of air per kg of coal | |
| 9. |
A chimney is 25 m high. The temperature of hot gases inside chimney is 300 C and temperature of air outside chimney is 30 C. If 20 kg of air is supplied to the furnace per kg of coal find the equivalent column of hot gases that would produce the same draught pressure. |
| A. | 20.02 m |
| B. | 22.40 m |
| C. | 24.42 m |
| D. | 22.60 m |
| Answer» B. 22.40 m | |
| 10. |
Calculate the draught in mm of water if the chimney height is 30 m, the temperatures of hot gases inside chimney and outside air are 330 C and 30 C respectively. Also, the furnace is supplied with 15 kg of air per kg of coal burnt. |
| A. | 14.67 mm of water |
| B. | 17.64 mm of water |
| C. | 16.22 mm of water |
| D. | 16.19 mm of water |
| Answer» D. 16.19 mm of water | |
| 11. |
Which of the following is the correct formula for calculating the pressure difference causing the gas flow through the combustion chamber? |
| A. | ( a g)gH |
| B. | ( a + g)gH |
| C. | ( g a)gH |
| D. | ( g + a)gH |
| Answer» B. ( a + g)gH | |
| 12. |
Natural draught is obtained using _____ |
| A. | Economizer |
| B. | Induced fan |
| C. | Chimney |
| D. | Induced and forced fan |
| Answer» D. Induced and forced fan | |
| 13. |
Artificial draught is classified into steam jet and mechanical draught. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 14. |
Draught is classified into _____ |
| A. | Artificial and natural draught |
| B. | Induced and forced draught |
| C. | Steam jet and mechanical draught |
| D. | Chimney draught and boiler draught |
| Answer» B. Induced and forced draught | |
| 15. |
What is draught? |
| A. | The condition of a dry boiler is called draught |
| B. | It s a small pressure difference which causes the flow of gases |
| C. | It is a boiler mounting |
| D. | It is a boiler accessory |
| Answer» C. It is a boiler mounting | |