McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 1. |
Which of the following cycle is less efficient as compared to the remaining? |
| A. | Carnot cycle |
| B. | All have identical efficiency |
| C. | Stirling cycle |
| D. | Ericsson cycle |
| E. | Otto cycle |
| Answer» E. Otto cycle | |
| 2. |
The number of degrees of freedom in case of triatomic gases is |
| A. | 5 |
| B. | 3 |
| C. | 6 |
| D. | 4 |
| E. | 2 |
| Answer» C. 6 | |
| 3. |
At critical point the enthalpy of vaporisation is |
| A. | Only dependent on temperature |
| B. | Zero |
| C. | Maximum |
| D. | Minimum |
| E. | None of the above |
| Answer» B. Zero | |
| 4. |
In which of the following case the process of sublimation can occur? |
| A. | Solid nitrogen |
| B. | Solid carbondioxide |
| C. | Liquid air |
| D. | Solid oxygen |
| E. | Sodium |
| Answer» B. Solid carbondioxide | |
| 5. |
Work done in a free expansion process is |
| A. | Negative |
| B. | Positive |
| C. | Maximum |
| D. | Zero |
| E. | Minimum |
| Answer» D. Zero | |
| 6. |
If a system neither exchange mass nor energy with the surroundings, it is known as |
| A. | Semi-closed system |
| B. | Isolated system |
| C. | Inactive system |
| D. | Closed system |
| E. | Segregated system |
| Answer» B. Isolated system | |
| 7. |
Food can be cooked quicker in a pressure cooker because |
| A. | Less heat is lost |
| B. | High pressure steam has high temperature |
| C. | Steam remains within the cooker |
| D. | It is made of a metal |
| E. | None of the above |
| Answer» C. Steam remains within the cooker | |
| 8. |
A surface which diffusely reflects and emits tha same amount of energy which it receives by radiation, is known as |
| A. | A perfect surface |
| B. | A perfect grey surface |
| C. | A perfect white surface |
| D. | A perfect radiating surface |
| E. | None of the above |
| Answer» D. A perfect radiating surface | |
| 9. |
Exhaust gases from a engine possess |
| A. | Chemical energy |
| B. | Solar energy |
| C. | Potential energy |
| D. | Stored energy |
| E. | Kinetic energy |
| Answer» E. Kinetic energy | |
| 10. |
Which one of the following is an indirect reaction device? |
| A. | Turbojet |
| B. | Ramjet |
| C. | Pulsejet |
| D. | Propeller |
| E. | All of the above |
| Answer» D. Propeller | |
| 11. |
Cetane number of a diesel fuel is a measure of its |
| A. | volatility |
| B. | Pulsejet |
| C. | delay period |
| D. | viscosity |
| E. | ignition quality |
| Answer» E. ignition quality | |
| 12. |
A thermistor is a |
| A. | Thermocouple |
| B. | Thermometer |
| C. | Thermos flask |
| D. | Miniature resistance |
| E. | None of the above |
| Answer» D. Miniature resistance | |
| 13. |
Which of the following is a reversible process? |
| A. | Extension and compression of a spring |
| B. | Diffusion |
| C. | Free expansion |
| D. | Throttling |
| E. | Combustion |
| Answer» A. Extension and compression of a spring | |
| 14. |
Power required for the engine is |
| A. | 7.75 kW |
| B. | 8.88 kW |
| C. | 9.23 kW |
| D. | 6.60 kW |
| E. | Pulsejet |
| Answer» C. 9.23 kW | |
| 15. |
According to Charle's law |
| A. | At constant pressure the volume of a gas is proportional to its temperature |
| B. | At constant pressure the volume of a gas is proportional to its absolute temperature |
| C. | At constant gauge pressure the molecular folume of a gas is proportional to its absolute temperature |
| D. | At constant volume the absolute pressure is proportional to absolute temperature |
| E. | None of the above |
| Answer» A. At constant pressure the volume of a gas is proportional to its temperature | |
| 16. |
The mean free path of a gas least depends on |
| A. | volume of gas |
| B. | viscosity of gas |
| C. | Pulsejet |
| D. | density of gas |
| E. | pressure of gas |
| Answer» A. volume of gas | |
| 17. |
The value of universal gas constant in S.I. units is |
| A. | 831.4 J/kg mole/?k |
| B. | 8314 J/kg mole/?k |
| C. | 8.314 J/kg mole/?k |
| D. | 83.14 J/kg mole/?k |
| E. | 0.8314 J/kg mole/?k |
| Answer» B. 8314 J/kg mole/?k | |
| 18. |
Which of the following valve is installed between the boiler and the feed pump? |
| A. | Flow of c*ck |
| B. | Pulsejet |
| C. | Steam stop valve |
| D. | Throttle valve |
| E. | Feed check valve |
| Answer» E. Feed check valve | |
| 19. |
Thermodynamic equilibrium is completely defined by the specifications of |
| A. | Internal energy |
| B. | Enthalpy |
| C. | Generalized displacements |
| D. | All the above together |
| E. | None of the above |
| Answer» D. All the above together | |
| 20. |
A gas (inversion temperature Ti) undergoing Joule Thomson expansion at temperature T will produce cooling effect only when |
| B. | Ti < T |
| C. | Ti > T |
| D. | Pulsejet |
| E. | Ti = T |
| Answer» B. Ti < T | |
| 21. |
During an adiabatic expansion, the increase in volume is associated with |
| A. | decrease in pressure and increase in temperature |
| B. | increase in pressure and decrease in temperature |
| C. | Decrease in pressure and decrease in temperature |
| D. | Pulsejet |
| E. | increase in pressure and increase in temperature |
| Answer» C. Decrease in pressure and decrease in temperature | |
| 22. |
The mean free path of a gas molecule increases with |
| A. | increase in pressure |
| B. | increase in density |
| C. | increase in temperature |
| D. | Pulsejet |
| E. | decrease in temperature |
| Answer» C. increase in temperature | |
| 23. |
In a Carnot cycle the heat is rejected at |
| A. | Constant pressure |
| B. | Constant temperature |
| C. | Constant entropy |
| D. | Constant enthalpy |
| E. | Constant volume |
| Answer» B. Constant temperature | |
| 24. |
Which of the following statement is incorrect? |
| A. | Total heat of steam is less than the total weight of dry and super saturated steam |
| B. | Total heat of super heated steam is more than the total heat of wet steam |
| C. | Latent heat of steam at critical pressure is zero |
| D. | Latent heat per kg of steam decreases as the pressure of steam increases |
| E. | None of the above |
| Answer» D. Latent heat per kg of steam decreases as the pressure of steam increases | |
| 25. |
Non-dimensional numbers generally involved in case of heat transfer from horizontal cylinders by natural convection are |
| A. | Reynolds number |
| B. | Nusselt number |
| C. | Prandtl number |
| D. | Grashof number |
| E. | (B), (C) and (D) above |
| Answer» E. (B), (C) and (D) above | |
| 26. |
Which of the following is the best fuel for diesel engines? |
| A. | Olefins |
| B. | Pulsejet |
| C. | Aromatics |
| D. | Naphthenes |
| E. | Paraffins |
| Answer» E. Paraffins | |
| 27. |
Air leaking from a punctured tube is an example of |
| A. | Throttling |
| B. | Constant volume expansion |
| C. | Adiabatic expansion |
| D. | Constant pressure expansion |
| E. | Isothermal expansion |
| Answer» A. Throttling | |
| 28. |
The percentage of carbondioxide in the exhaust gases from a diesel engine cannot exceed |
| A. | 40% |
| B. | 50.50% |
| C. | 29% |
| D. | 36% |
| E. | 55% |
| Answer» C. 29% | |
| 29. |
Internal energy of a perfect gas depends on |
| A. | Temperature, specific heats and entropy |
| B. | Temperature, specific heats and pressure |
| C. | Temperature, specific heats and enthalpy |
| D. | Temperature and specific heats |
| E. | Temperature only |
| Answer» E. Temperature only | |
| 30. |
The process during which external work done is not zero, is |
| A. | Constant volume process |
| B. | Constant pressure process |
| C. | Throttling |
| D. | Free expansion |
| E. | All of the above |
| Answer» B. Constant pressure process | |
| 31. |
Which of the following cycle consists of two isothermal and constant volume processes? |
| A. | Joule cycle |
| B. | Diesel cycle |
| C. | Rankine cycle |
| D. | Otto cycle |
| E. | Ericsson cycle |
| Answer» E. Ericsson cycle | |
| 32. |
A perfect black body is |
| A. | One which absorbs all radiant energy at all wavelengths |
| B. | One which does not reflect the radiant energy |
| C. | Black in colour |
| D. | One through which radiant energy is not transmitted |
| E. | One which absorbs total radiant energy |
| Answer» A. One which absorbs all radiant energy at all wavelengths | |
| 33. |
The characteristics of a control volume are |
| A. | There is no material flow across the boundary |
| B. | The volume, shape and position with respect to an observer may change |
| C. | Pulsejet |
| D. | The volume, shape and position with respect to an observer are fixed |
| Answer» D. The volume, shape and position with respect to an observer are fixed | |
| 34. |
By doubling the temperature the radiant heat will increase |
| A. | 16 times |
| B. | microns |
| C. | 4 times |
| D. | 8 times |
| E. | 2 times |
| Answer» A. 16 times | |
| 35. |
Which of the following is not a property of the system |
| A. | Temperature |
| B. | Pressure |
| C. | Specific volume |
| D. | Heat |
| E. | None of the above |
| Answer» D. Heat | |
| 36. |
The mixture formation in a carburettor is based on the principle of |
| A. | Venturi principle |
| B. | Pascal's law |
| C. | Law of vapours |
| D. | Daltons law |
| E. | Newtons law of motion |
| Answer» A. Venturi principle | |
| 37. |
Heating wet steam at constant temperature is same as heating at |
| A. | Constant pressure |
| B. | Constant volume |
| C. | Constant enthalpy |
| D. | Constant entropy |
| E. | None of the above |
| Answer» A. Constant pressure | |
| 38. |
A liquid flowing through a tube is turbulent. In which case will the maximum change in heat transfer coefficient occur? |
| A. | Diameter of the tube is increased 4 time maintaining the ratio of liquid flow constant |
| B. | Diameter of the tube is increased 4 times maintaining the velocity of flow constant |
| C. | Diameter of the tube is increased 2 times maintaining the rate of liquid flow constant |
| D. | Diameter of the tube is increased 2 times maintaining the velocity of flow constant |
| E. | microns |
| Answer» A. Diameter of the tube is increased 4 time maintaining the ratio of liquid flow constant | |
| 39. |
All of the following cycles consists of two isothermal processes EXCEPT |
| A. | Ericsson cycle |
| B. | Stirling cycle |
| C. | Brayton cycle |
| D. | Carnot cycle |
| E. | Pulsejet |
| Answer» C. Brayton cycle | |
| 40. |
Which of the following introduces irreversibility in the actual Carnot engine operation? |
| A. | Higher operating speeds |
| B. | Losses from working fluid in transit |
| C. | Pulsejet |
| D. | Changes in pressure and temperature during the cycle |
| E. | Friction between moving parts |
| Answer» B. Losses from working fluid in transit | |
| 41. |
Which of the following is the best fuel for S.I. engines? |
| A. | Naphthenes |
| B. | Olefins |
| C. | Aromatics |
| D. | Pulsejet |
| E. | Paraffins |
| Answer» C. Aromatics | |
| 42. |
The cycle generally used for gas turbines is |
| A. | Brayton cycle |
| B. | Carnot cycle |
| C. | Dual cycle |
| D. | Otto cycle |
| E. | Rankine cycle |
| Answer» A. Brayton cycle | |
| 43. |
The slope of constant pressure line on temperature entropy diagrm is given by |
| A. | 90? |
| B. | T/Cp |
| C. | Cp/T |
| D. | S/T |
| E. | T/S |
| Answer» B. T/Cp | |
| 44. |
In automobiles clutch is mounted between |
| A. | Gear box and differential |
| B. | Differential and wheels |
| C. | Engine and flywheel |
| D. | Engine and differential |
| E. | Flywheel and gear box |
| Answer» E. Flywheel and gear box | |
| 45. |
During an adiabatic process the change in entropy is |
| A. | Positive or Negative |
| B. | Zero |
| C. | Negative |
| D. | Approximately zero |
| E. | Positive |
| Answer» B. Zero | |
| 46. |
The behaviour of which of the following vapour is closer to that of a gas? |
| A. | Wet vapour |
| B. | Wet and superheated vapours |
| C. | Wet and dry vapour |
| D. | Superheated vapour |
| E. | Dry vapour |
| Answer» D. Superheated vapour | |
| 47. |
The ratio of the rise in temperature of a gas when compressed adiabatically to that when compressed isothermally to the same extent is |
| A. | Depends on the gas |
| B. | Pulsejet |
| C. | less than 1 |
| D. | Equal to 1 |
| E. | More than 1 |
| Answer» E. More than 1 | |
| 48. |
In all irreversible processes, the entropy of the system |
| A. | Increases |
| B. | Depends on medium |
| C. | Remains constant |
| D. | Sometimes increases and sometimes decreases |
| E. | Reduces to zero |
| Answer» A. Increases | |
| 49. |
Which of the following remains constant during an adiabatic process? |
| A. | internal energy |
| B. | enthalpy |
| C. | entropy |
| D. | All of the above |
| E. | Pulsejet |
| Answer» C. entropy | |
| 50. |
Reduced pressure is |
| A. | dimensionless |
| B. | an index of molecular position of gas |
| C. | always unity |
| D. | Pulsejet |
| E. | always less than atmospheric pressure |
| Answer» A. dimensionless | |
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