McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 251. |
On a Mollier chart the flow through turbine is represented by |
| A. | Horizontal line |
| B. | Vertical line |
| C. | Curved line convex up |
| D. | Carved line convex down |
| E. | None of the above |
| Answer» B. Vertical line | |
| 252. |
Which of the following turbines cannot be set below the maximum tail race level |
| A. | Kaplan |
| B. | Pelton |
| C. | Francis |
| D. | Propeller |
| E. | Energyless process |
| Answer» A. Kaplan | |
| 253. |
The fact that the product of pressure and volume of a fixed amount of gas is of approximately constant value is known as |
| A. | Dalton's law |
| B. | None of these |
| C. | Gay Lussac's law |
| D. | Charle's law |
| E. | Lewis law |
| Answer» B. None of these | |
| 254. |
Steady state heat transfer occurs when |
| A. | The flow of heat is uniformly decreasing |
| B. | The flow of heat is uniform |
| C. | The flow of heat is independent of time |
| D. | The flow of heat is negligible |
| E. | The flow of heat is uniformly increasing |
| Answer» C. The flow of heat is independent of time | |
| 255. |
The air standard efficiency of a turbine cycle is 57%. Which one of the following may be Carnot efficiency between the temperature limits of the cycle? |
| A. | 57% |
| B. | 50% |
| C. | 64% |
| D. | 55% |
| E. | 100% |
| Answer» C. 64% | |
| 256. |
"It is impossible to construct a heat engine which operates in a cycle and receives a given amount of heat from a high temperature body and does equal amount of work". Which of the following name is associated with the above statement? |
| A. | Gay Lussac |
| B. | Kinetic theory |
| C. | Kelvin-planck |
| D. | Joule-thomson |
| E. | None of the above |
| Answer» C. Kelvin-planck | |
| 257. |
For a reversible adiabatic process the change in entropy is |
| A. | Unity |
| B. | Zero |
| C. | Maximum |
| D. | Minimum |
| E. | Infinite |
| Answer» B. Zero | |
| 258. |
Whenever a system undergoes either a change in state or an energy or mass transfer at a steady state, it is said to undergo |
| A. | A steady state transfer |
| B. | A thermodynamic change |
| C. | An equilibrium |
| D. | A process |
| E. | A change of state |
| Answer» D. A process | |
| 259. |
In case the thermal efficiency of an engine becomes 100% it will violate |
| A. | Zeroth law of thermodynamics |
| B. | First law of thermodynamics |
| C. | Second law of thermodynamics |
| D. | Third law of thermodynamics |
| E. | None of the above |
| Answer» C. Second law of thermodynamics | |
| 260. |
The number of degrees of freedom for a diatomic molecule is |
| A. | 3 |
| B. | 6 |
| C. | 5 |
| D. | 4 |
| E. | Pulsejet |
| Answer» C. 5 | |
| 261. |
Which of the following is not a positive displacement compressor? |
| A. | Centrifugal compressor? |
| B. | Vane type compressor |
| C. | Roots blower |
| D. | Double acting reciprocating compressor |
| E. | Single stage reciprocating compressor |
| Answer» A. Centrifugal compressor? | |
| 262. |
The internal energy of a substance depdnds on |
| A. | Velocity |
| B. | Pressure |
| C. | Entropy |
| D. | Temperature |
| E. | Volume |
| Answer» D. Temperature | |
| 263. |
According to Kinetic theory of gases, at absolute zero |
| A. | Pressure of gas will reduce to zero |
| B. | Mass of gas will reduce to zero |
| C. | Volume of gas will reduce to zero |
| D. | Kinetic energy of gas molecules will reduce to zero |
| E. | Specific heat of molecules will reduce to zero |
| Answer» D. Kinetic energy of gas molecules will reduce to zero | |
| 264. |
The temperature of a gas is a measure of |
| A. | the average kinetic energy of the gaseous molecules |
| B. | the average distance between the molecules of the gas |
| C. | The average potential energy of the molecules |
| D. | None of the above |
| E. | Pulsejet |
| Answer» A. the average kinetic energy of the gaseous molecules | |
| 265. |
Which of the following is conserved across a shock wave? |
| A. | Temperature |
| B. | Pressure |
| C. | Momentum |
| D. | All of the above |
| E. | Temperature remains constant |
| Answer» C. Momentum | |
| 266. |
A cycle which consists of two adiabatic and two constant volume processes is known as |
| A. | Pulsejet |
| B. | Diesel cycle |
| C. | Carnot cycle |
| D. | Stirling cycle |
| E. | Otto cycle |
| Answer» E. Otto cycle | |
| 267. |
If the roof of a house is replaced by a shiny metallic surface the temperature inside will |
| A. | microns |
| B. | Decrease |
| D. | Increase |
| E. | Remain unaltered |
| Answer» B. Decrease | |
| 268. |
In an isothermal process |
| A. | Pressure remains constant |
| B. | Change in internal energy is zero |
| C. | Enthalpy change is maximum |
| D. | Volume remains constant |
| E. | Temperature increases gradually |
| Answer» B. Change in internal energy is zero | |
| 269. |
A 500 litre tank contains a saturated mixture of steam and water at 300?C. If the mass of steam and water within the tank is equal, it can be concluded that |
| A. | Steam will be nearly dry and saturated |
| B. | volume of steam will be less than the volume of water |
| C. | Pulsejet |
| D. | Dryness fraction of steam will be closer to 0.5 |
| E. | Volume of steam will be less than the volume of water |
| Answer» E. Volume of steam will be less than the volume of water | |
| 270. |
When a fluid is passed in steady, flow through a porous plug in a duct under such conditions that heat transfer, kinetic energy change and potential change is negligible, the process is called |
| A. | Throttling |
| B. | Separation |
| C. | Constant pressure compression |
| D. | Isothermal compression |
| E. | Frictionless compression |
| Answer» A. Throttling | |
| 271. |
In adiabatic compression the decrease in volume is associated with |
| A. | Pulsejet |
| B. | decrease in temperature and increase in pressure |
| C. | increase in temperature and increase in pressure |
| D. | increase in temperature and decrease in pressure |
| E. | decrease in temperature and decrease in pressure |
| Answer» C. increase in temperature and increase in pressure | |
| 272. |
A Brayton cycle is also a reversed |
| A. | Carnot cycle |
| B. | Dual cycle |
| C. | Joule cycle |
| D. | Otto cycle |
| E. | Rankine cycle |
| Answer» C. Joule cycle | |
| 273. |
For diatomic gas flowing through a nozzle the critical pressure ratio is given by |
| A. | 0.577 |
| B. | 0.546 |
| C. | 0.75 |
| D. | 1 |
| E. | 0.528 |
| Answer» E. 0.528 | |
| 274. |
The molecular volume of any perfect gas at 600 x 103 N/m3 and 27?C will be |
| A. | 41.7 m3/kg mol |
| B. | 4.17 m3/kg mol |
| C. | 47.7 m3/kg mol |
| D. | 2.085 m3/kg mol |
| E. | 85.3 m3/kg mol |
| Answer» B. 4.17 m3/kg mol | |
| 275. |
In a 2 stroke engine we get one power stroke in |
| A. | 180? of crank rotation |
| B. | 540? of crank rotation |
| C. | 360? of crank rotation |
| D. | 270? of crank rotation |
| E. | 720? of crank rotation |
| Answer» C. 360? of crank rotation | |
| 276. |
The perfect heat engine works on the Carnot cycle between 1000?C and 200?C. The efficiency of the engine will be |
| A. | 60% |
| B. | 68.20% |
| C. | 37.20% |
| D. | 80% |
| E. | 62.80% |
| Answer» E. 62.80% | |
| 277. |
Joule Thomson coefficient for an ideal gas having equation pv = RT is |
| A. | Zero |
| B. | 0.5 |
| C. | ?100?C |
| D. | Unity |
| Answer» A. Zero | |
| 278. |
The efficiency of a dicsel cycle will be maximum when |
| A. | Engine is super-charged |
| B. | Cylinder is water cooled |
| C. | Injection pressure is high |
| D. | Cut off is zero |
| E. | Speed is high |
| Answer» D. Cut off is zero | |
| 279. |
Thermodynamic equilibrium is completely defined by the specifications of |
| A. | Internal energy |
| B. | Generalized displacement |
| C. | All the above together |
| D. | None of the above |
| E. | It is dimensionless |
| Answer» D. None of the above | |
| 280. |
In the polytropic process equation pvn Constant, if n = 0 the process is termed as |
| A. | Constant volume |
| B. | Constant pressure |
| C. | Isothermal |
| D. | Constant temperature |
| E. | Adiabatic |
| Answer» B. Constant pressure | |
| 281. |
Out of the following materials which may be expected to have higher value of thermal conductivity? |
| A. | Asbestos |
| B. | Refractory brick |
| C. | Wood |
| D. | Clay |
| E. | Nichrome |
| Answer» E. Nichrome | |
| 282. |
In a Carnot engine, when the working substance gives heat to the sink |
| A. | Changes depend on the operating conditions |
| B. | The temperature of the sink increases |
| C. | The temperature of both the sink and the source decreases |
| D. | The temperature of the sink remains the same |
| E. | The temperature of the source decreases |
| Answer» D. The temperature of the sink remains the same | |
| 283. |
Which of the following is not a property of the system? |
| A. | Temperature |
| B. | Pressure |
| C. | Specific volume |
| D. | Work |
| E. | None of the above |
| Answer» D. Work | |
| 284. |
Which of the engine is used for fighter bombers? |
| A. | Pulsejet |
| B. | Ramjet |
| C. | Turbo prop |
| D. | Rockets |
| E. | Turbojet |
| Answer» E. Turbojet | |
| 285. |
A gas can never be liquid |
| A. | Above critical temperature |
| B. | When it is diatomic |
| C. | When it is impure |
| D. | When it is reactive with any other gas |
| E. | Above room temperature |
| Answer» A. Above critical temperature | |
| 286. |
A mixture of liquid and vapour Freon in a vessel is an example of |
| A. | Isolated system |
| B. | Heterogeneous system |
| C. | Open system |
| D. | Closed system |
| E. | Transient system |
| Answer» B. Heterogeneous system | |
| 287. |
Heat exchanger used in a steam condenser of a thermal power plant is |
| A. | Direct contact type |
| B. | Recuperator type |
| C. | Regenerator type |
| D. | Any one of the above |
| E. | None of the above |
| Answer» B. Recuperator type | |
| 288. |
A piece of paper wrapped tightly on a copper rod will get charred relatively slowly when held over a flame as compared to a piece of paper wrapped tightly on any of the following rod except |
| A. | silver rod |
| B. | iron rod |
| C. | Pulsejet |
| D. | brass rod |
| E. | wooden rod |
| Answer» A. silver rod | |
| 289. |
Three engines A, B and C operating on Carnot cycle use working substances as oxygen, hydrogen and air. Which engine will have higher efficiency? |
| A. | Engine C |
| B. | All will have the same efficiency |
| C. | Pulsejet |
| D. | Engine B |
| E. | Angine A |
| Answer» B. All will have the same efficiency | |
| 290. |
In a diesel engine fuel is injected |
| A. | after the end of compression stroke |
| B. | at the beginning of compression stroke |
| C. | at the end of compression stroke |
| D. | before the end of compression stroke |
| E. | Pulsejet |
| Answer» D. before the end of compression stroke | |
| 291. |
The molecular volume of all the gases at 2 ata and 30?C is |
| A. | 12.847 cu-m |
| B. | 1.562 cu-m |
| C. | 25.794 cu-m |
| D. | 8.48 cu-m |
| E. | 1.0 cm-m |
| Answer» A. 12.847 cu-m | |
| 292. |
Other factors remaining constant, if the temperature of source is increased, the efficiency of Carnot engine will |
| A. | will not change |
| B. | decrease |
| C. | Pulsejet |
| D. | increase or decrease depending upon temperature ratio |
| E. | increase |
| Answer» E. increase | |
| 293. |
The sequence of processes that eventually returns the working substance to its original state is known as |
| A. | Thermodynamic cycle |
| B. | Process |
| C. | Zeroth law of thermodynamics |
| D. | Event |
| E. | Thermodynamic property |
| Answer» A. Thermodynamic cycle | |
| 294. |
Which of the following is not a path function? |
| A. | Work |
| B. | Heat |
| C. | Kinetic energy |
| D. | Thermal conductivity |
| E. | All of the above |
| Answer» D. Thermal conductivity | |
| 295. |
In axial flow compressors, the phenomenon of stalling of blades occurs when |
| A. | Air stream is not able to follow the blade contour |
| B. | Blades vibrate violently |
| C. | Air stream flows with sonic velocity |
| D. | Air stream blocks the passage |
| E. | Blades fail due to creep |
| Answer» A. Air stream is not able to follow the blade contour | |
| 296. |
COP of the engine is |
| A. | 5.33 |
| B. | 4.33 |
| C. | 3.33 |
| D. | 2.33 |
| E. | Pulsejet |
| Answer» B. 4.33 | |
| 297. |
A diathermic wall permits |
| A. | Radiation heat flow only |
| B. | Conduction heat flow only |
| C. | No heat exchange |
| D. | Heat exchange by all the three modes of heat transfer |
| E. | Convective heat flow only |
| Answer» D. Heat exchange by all the three modes of heat transfer | |
| 298. |
Which of the following is not a reversible cycle? |
| A. | Carnot cycle |
| B. | Stirling cycle |
| C. | Ericsson cycle |
| D. | Otto cycle |
| E. | All of the above |
| Answer» D. Otto cycle | |
| 299. |
In which case the heat transferred from the air when compressed from 1 ata 15?C to 6 ata would be maximum |
| A. | Adiabatic |
| B. | Polytropic pv1.35 = C |
| C. | Polytropic pv1.3 = C |
| D. | Polytropic pv1.31 = C |
| E. | Isothermal |
| Answer» A. Adiabatic | |
| 300. |
The dimensions of 'a' will be |
| A. | Pulsejet |
| B. | ML2T |
| C. | ML6T-2 |
| D. | ML3T-2 |
| E. | ML5T-2 |
| Answer» E. ML5T-2 | |
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