MCQOPTIONS
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MCQOPTIONS
This section includes 10 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. |
Air enters a frictionless adiabatic horizontal nozzle at 12 bar and 167 C with inlet velocity 50 m/s and leaves at 3 bar. Take adiabatic index equal to 1.4 and cp = 1.005 kJ/kg-K. |
| A. | 654.78 m/s |
| B. | 321.75 m/s |
| C. | 552.45 m/s |
| D. | 456.87 m/s |
| Answer» D. 456.87 m/s | |
| 2. |
Air at 18 bar and 100 C enters a convergent nozzle. Assume the flow to be isentropic and calculate the sonic velocity. Take adiabatic index equal to 1.4. |
| A. | 353.40 m/s |
| B. | 321.56 m/s |
| C. | 360.87 m/s |
| D. | 400.32 m/s |
| Answer» B. 321.56 m/s | |
| 3. |
The purpose of a steam injector is to force water into the boiler under pressure. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4. |
Which of the following conditions correspond to divergent type diffuser? |
| A. | M < 1 and ( frac{dA}{A} )>0 |
| B. | M < 1 and ( frac{dA}{A} )>0 |
| C. | M < 1 and ( frac{dA}{A} )<0 |
| D. | M > 1 and ( frac{dA}{A} )<0 |
| Answer» B. M < 1 and ( frac{dA}{A} )>0 | |
| 5. |
A decelerated flow, having fluid velocity greater than the local sonic velocity corresponds to _____ |
| A. | Convergent part of a nozzle |
| B. | Divergent part of a nozzle |
| C. | Convergent part of a diffuser |
| D. | Divergent part of a diffuser |
| Answer» D. Divergent part of a diffuser | |
| 6. |
Which of the following conditions corresponds to divergent part of a nozzle? |
| A. | M < 1 and ( frac{dP}{P} ) > 0 |
| B. | M < 1 and ( frac{dP}{P} ) < 0 |
| C. | M > 1 and ( frac{dP}{P} ) < 0 |
| D. | M > 1 and ( frac{dP}{P} ) > 0 |
| Answer» D. M > 1 and ( frac{dP}{P} ) > 0 | |
| 7. |
Which of the following statements regarding the Mach number is TRUE, when the fluid reaches the throat of a nozzle? |
| A. | It becomes unity |
| B. | It is less than one |
| C. | It is greater than one |
| D. | Mach number is not defined at throat of a nozzle |
| Answer» B. It is less than one | |
| 8. |
In case of accelerated flow, when the pressure decreases along the flow direction and Mach number is less than one, it corresponds to _____ |
| A. | Convergent part of a nozzle |
| B. | Divergent part of a nozzle |
| C. | Throat of a nozzle |
| D. | Convergent part of a diffuser |
| Answer» B. Divergent part of a nozzle | |
| 9. |
Which of the following expressions is correct? (P fluid pressure, M- Mach number, A cross-sectional area of nozzle/diffuser) |
| A. | ( frac{dA}{A}= frac{1}{ } frac{dP}{P} big { frac{M^2}{1-M^2} big } ) |
| B. | ( frac{dA}{A}= frac{1}{ } frac{dP}{P} big { frac{M^2-1}{M^2} big } ) |
| C. | ( frac{dA}{A}= frac{1}{ } frac{dP}{P} big { frac{1-M^2}{M^2} big } ) |
| D. | ( frac{1}{ } frac{dA}{A}= frac{dP}{P} big { frac{1-M^2}{M^2} big } ) |
| Answer» D. ( frac{1}{ } frac{dA}{A}= frac{dP}{P} big { frac{1-M^2}{M^2} big } ) | |
| 10. |
Which of the following expressions correctly represents the relationship between cross-sectional area of a nozzle, fluid velocity and specific volume? |
| A. | ( frac{dA}{A}+ frac{dC}{C}= frac{dv}{v} ) |
| B. | ( frac{dA}{A}- frac{dC}{C}= frac{dv}{v} ) |
| C. | ( frac{dA}{A}+ frac{dC}{C}+ frac{dv}{v} ) = 0 |
| D. | ( frac{dA}{A}+ frac{dv}{v}= frac{dC}{C} ) |
| Answer» B. ( frac{dA}{A}- frac{dC}{C}= frac{dv}{v} ) | |