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. |
Which of the following is compressed in diesel engine? |
| A. | Air |
| B. | Air and fuel |
| C. | Air and lubricating oil |
| D. | Fuel |
| Answer» B. Air and fuel | |
| 2. |
The combustion in compression ignition engine is __________ |
| A. | Homogenous |
| B. | Heterogeneous |
| C. | Laminar |
| D. | Turbulent |
| Answer» C. Laminar | |
| 3. |
A diesel engine is usually more efficient than a spark ignition engine because ___________ |
| A. | Diesel being a heavier hydrocarbon, release more heat per kg than gasoline |
| B. | The air standard efficiency of diesel engine is higher than the otto cycle, at a fixed compression ratio |
| C. | The compression ratio of diesel engine is higher than petrol engine |
| D. | Self ignition temperature of diesel engine is higher than that of gasoline |
| Answer» D. Self ignition temperature of diesel engine is higher than that of gasoline | |
| 4. |
Scavenging in diesel cycle means___________ |
| A. | Air used for combustion under pressure |
| B. | Forced air for cooling the cylinder |
| C. | Burnt air containing products of combustion |
| D. | Air used for forcing burnt gases out of engines cylinder during exhaust stroke |
| Answer» E. | |
| 5. |
What is the efficiency of diesel cycle if γ and T denotes the specific heat ratio and temperature respectively? |
| A. | 1 – \(\frac{T4-T1}{T3-T2} \) |
| B. | 1 – \(\frac{T4-T1}{γ(T3-T2)} \) |
| C. | 1 – \(\frac{γ(T4-T1)}{T3-T2} \) |
| D. | 1 – \(\frac{T4-T1}{(γ-1)(T3-T2)} \) |
| Answer» C. 1 – \(\frac{γ(T4-T1)}{T3-T2} \) | |
| 6. |
What is the value of working fluid in diesel cycle? |
| A. | 1 |
| B. | 1.2 |
| C. | 1.4 |
| D. | 1.8 |
| Answer» D. 1.8 | |
| 7. |
For same peak pressure and heat input _________ |
| A. | Otto cycle is more efficient |
| B. | Diesel cycle is more efficient |
| C. | Dual cycle is more efficient |
| D. | Both diesel and otto cycle are equally efficient |
| Answer» C. Dual cycle is more efficient | |
| 8. |
The compression ratio (rk) of diesel cycle is equal to ___________ |
| A. | rk = volume of the cylinder at the beginning of the compression/volume of the cylinder at the end of the compression |
| B. | rk = volume of the cylinder at the end of the compression/ volume of the cylinder at the beginning of the compression |
| C. | rk = clearance volume/ volume of the cylinder at the beginning of the compression |
| D. | rk = volume of the cylinder at the end of the compression/clearance volume |
| Answer» B. rk = volume of the cylinder at the end of the compression/ volume of the cylinder at the beginning of the compression | |
| 9. |
An air standard diesel cycle consist of ___________ |
| A. | One constant pressure process and three adiabatic process |
| B. | One constant pressure process, one constant volume process and two adiabatic process |
| C. | Two constant volume process and two adiabatic process |
| D. | Two constant pressure process and two adiabatic process |
| Answer» C. Two constant volume process and two adiabatic process | |
| 10. |
The thermal efficiency of diesel cycle having fixed cut-off ratio, with increase in compression ratio. |
| A. | Increases |
| B. | Decreases |
| C. | Be independent |
| D. | Data insufficient |
| Answer» B. Decreases | |
| 11. |
The thermal efficiency of diesel cycle having fixed compression ratio, with increase in cut-off ratio. |
| A. | Increases |
| B. | Decreases |
| C. | Be independent |
| D. | Data insufficient |
| Answer» C. Be independent | |
| 12. |
In diesel engine fuel is ignited by ___________ |
| A. | Fuel injection |
| B. | Spark |
| C. | Heat resulting from compressing air |
| D. | Heat resulting from compression of air fuel mixture |
| Answer» B. Spark | |
| 13. |
In diesel cycle heat addition occurs at ___________ |
| A. | Reversible constant volume process |
| B. | Reversible constant pressure process |
| C. | Irreversible constant volume process |
| D. | Irreversible constant pressure process |
| Answer» C. Irreversible constant volume process | |
| 14. |
In diesel cycle heat rejection occurs at ___________ |
| A. | Reversible constant volume process |
| B. | Reversible constant pressure process |
| C. | Irreversible constant volume process |
| D. | Irreversible constant pressure process |
| Answer» B. Reversible constant pressure process | |
| 15. |
Which cycle is idealized cycle for the compression ignition engines? |
| A. | Otto cycle |
| B. | Diesel cycle |
| C. | Dual cycle |
| D. | Bryton cycle |
| Answer» C. Dual cycle | |