MCQOPTIONS
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MCQOPTIONS
This section includes 430 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
During adiabatic expansion which of the following remains constant |
| A. | Internal energy |
| B. | Temperature |
| C. | Entropy |
| D. | None of the above |
| E. | Pulsejet |
| Answer» D. None of the above | |
| 202. |
One watt is the same as |
| A. | 100 Nm/s |
| B. | 10 Nm/s |
| C. | 1 Nm/s |
| D. | 1 Nm/min |
| E. | 10 Nm/min |
| Answer» D. 1 Nm/min | |
| 203. |
The average pressure on the walls of a vessel will be doubled if the |
| A. | average velocity of the molecules in it is doubled |
| B. | the number of molecules in the vessel is doubled |
| C. | Pulsejet |
| D. | the mass of each molecule is halved |
| E. | the mass of each molecule is doubled |
| Answer» C. Pulsejet | |
| 204. |
The specific heat of a perfect gas is a function of |
| A. | temperature, pressure and entropy only |
| B. | temperature only |
| C. | temperature and pressure only |
| D. | Pulsejet |
| E. | temperature and entropy only |
| Answer» C. temperature and pressure only | |
| 205. |
Clog point of an oil is |
| A. | The point of maximum contamination of oil |
| B. | The level of impurities beyond which oil ceases to flow |
| C. | The temperature at which oil solidifies |
| D. | The temperature at which paraffin and waxes in oil start precipitating |
| E. | None of the above |
| Answer» E. None of the above | |
| 206. |
The total radiant energy emitted by a plane surface per unit area and unit time is called |
| A. | Radiant flux density |
| B. | Total absorptivity |
| C. | Radiant energy |
| D. | Radiant intensity |
| E. | None of the above |
| Answer» B. Total absorptivity | |
| 207. |
Which of the following relation is not valid for throttling process? |
| A. | Enthalpy before expansion = Enthalpy after expansion |
| B. | Pressure before expansion = pressure after expansion |
| C. | External work done = Zero |
| D. | Mass before expansion = mass after expansion |
| E. | None of the above |
| Answer» C. External work done = Zero | |
| 208. |
The rate of diffusion along a column of certain cross-sectional area is proportional to the concentration gradient. Above statement is known as |
| A. | Thompson's law |
| B. | Law of diffusion |
| C. | Kirchhoff's law |
| D. | Fick's law |
| E. | None of the above |
| Answer» E. None of the above | |
| 209. |
The process that follows the equation pvn = constant, is called |
| A. | Adiabatic process |
| B. | Constant pressure process |
| C. | Constant volume process |
| D. | Constant temperature process |
| E. | Polytropic process |
| Answer» F. | |
| 210. |
At critical point the latent enthalpy of vaporisation is |
| A. | Only depends on temperature |
| B. | Zero |
| C. | Maximum |
| D. | Minimum |
| E. | None of the above |
| Answer» C. Maximum | |
| 211. |
Theoretically in a petrol engine during which stroke both suction as well as exhaust valves will remain closed? |
| A. | Suction stroke |
| B. | Exhaust stroke |
| C. | Both suction and exhaust strokes |
| D. | None of the above |
| E. | Pulsejet |
| Answer» E. Pulsejet | |
| 212. |
Wavelength is generally measured in |
| A. | microns |
| B. | mm |
| C. | km |
| D. | m |
| E. | cm |
| Answer» B. mm | |
| 213. |
If molar Cp = 4.97 then |
| A. | Cv = 2.97 |
| B. | Cv = 0.97 |
| C. | Cv = 5.97 |
| D. | Cv = 0.597 |
| E. | Cv = 1.97 |
| Answer» B. Cv = 0.97 | |
| 214. |
In an optimum four stage compressor system the first and third stage pressure are 1 kg/cm2 and 9 kg/cm2 respectively what will be the fourth stage delivery pressure? |
| A. | 81 kg/cm2 |
| B. | 27 kg/cm2 |
| C. | 9 kg/cm2 |
| D. | 6 kg/cm2 |
| E. | 3 kg/cm2 |
| Answer» B. 27 kg/cm2 | |
| 215. |
Kelvin's law deals with |
| A. | conservation of work |
| B. | conservation of heat |
| C. | conversion of work into heat |
| D. | conversion of heat into work |
| E. | Pulsejet |
| Answer» E. Pulsejet | |
| 216. |
In unsteady state, heat transfer occurs when |
| A. | The body through which heat flow is in motion |
| B. | The source of heat is in motion |
| C. | The heat flow changes with change in temperature |
| D. | The heat flow changes with time |
| E. | None of the above |
| Answer» E. None of the above | |
| 217. |
Gas laws are applicable to |
| A. | Gases and dry, wet and super-heated vapours |
| B. | Gases only |
| C. | Gases and dry and wet vapours |
| D. | Gases and wet vapours |
| E. | Gases and dry vapours |
| Answer» C. Gases and dry and wet vapours | |
| 218. |
1 kgf/cm2 is equal to |
| A. | 776 mm Hg |
| B. | 1 mm Hg |
| C. | 760 mm Hg |
| D. | 735.6 mm Hg |
| E. | 100 mm Hg |
| Answer» E. 100 mm Hg | |
| 219. |
The unit of Universal Gas constant is |
| A. | Dynes/?K |
| B. | erg/?K |
| C. | kcal/?K |
| D. | It is dimensionless |
| E. | W/m?K |
| Answer» C. kcal/?K | |
| 220. |
The rate of radiant energy, which is emitted by a surface at any temperature and in small wavelengths is found from the known rate of energy, which under the same conditions would be emitted from a black surface, by multiplying with the absorptivity. Above enunciation is known as |
| A. | Planck's law |
| B. | Kirchhoff's law |
| C. | Stefan Bolzmann's law |
| D. | Lambart's rule |
| E. | None of the above |
| Answer» C. Stefan Bolzmann's law | |
| 221. |
The value of the product of molecular weight and the gas characteristic constant for all gases in kgf m/1 kg mol ?K is |
| A. | 848 |
| B. | 427 |
| C. | 770 |
| D. | 29.27 |
| E. | 30 |
| Answer» C. 770 | |
| 222. |
A process which does not dissipate available energy is known as |
| A. | Isothermal process |
| B. | Energyless process |
| C. | Adiabatic process |
| D. | Ideal process |
| E. | Frictionless process |
| Answer» E. Frictionless process | |
| 223. |
Maxwells relations are valid for |
| A. | compressible substances |
| B. | all substances solid, liquid or gas |
| C. | systems of fixed chemical compositions |
| D. | Pulsejet |
| E. | homogeneous as well as heterogeneous systems |
| Answer» B. all substances solid, liquid or gas | |
| 224. |
Line's liquifer is based on the principle of |
| A. | Pulsejet |
| B. | Joule-Thomson effect |
| C. | adiabatic magnetisation |
| D. | adiabatic expansion |
| E. | adiabatic demagnetisation |
| Answer» E. adiabatic demagnetisation | |
| 225. |
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» C. Pulsejet | |
| 226. |
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» C. Open system | |
| 227. |
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» F. | |
| 228. |
Which of the engine is used for fighter bombers? |
| A. | Pulsejet |
| B. | Ramjet |
| C. | Turbo prop |
| D. | Rockets |
| E. | Turbojet |
| Answer» F. | |
| 229. |
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» E. Convective heat flow only | |
| 230. |
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» E. None of the above | |
| 231. |
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» B. Blades vibrate violently | |
| 232. |
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» B. Process | |
| 233. |
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» C. Regenerator type | |
| 234. |
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» B. Polytropic pv1.35 = C | |
| 235. |
COP of the engine is |
| A. | 5.33 |
| B. | 4.33 |
| C. | 3.33 |
| D. | 2.33 |
| E. | Pulsejet |
| Answer» C. 3.33 | |
| 236. |
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» B. 1.562 cu-m | |
| 237. |
The dimensions of 'a' will be |
| A. | Pulsejet |
| B. | ML2T |
| C. | ML6T-2 |
| D. | ML3T-2 |
| E. | ML5T-2 |
| Answer» F. | |
| 238. |
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» E. Speed is high | |
| 239. |
A scavenging pump is used in |
| A. | Pulsejet |
| B. | vapour compression cycles |
| C. | two stroke spark ignition engines |
| D. | steam engines |
| E. | four stroke compression ignition engines |
| Answer» D. steam engines | |
| 240. |
Joule Thomson coefficient for an ideal gas having equation pv = RT is |
| A. | Zero |
| B. | 0.5 |
| C. | ?100?C |
| D. | Unity |
| Answer» B. 0.5 | |
| 241. |
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» D. All of the above | |
| 242. |
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» D. increase in temperature and decrease in pressure | |
| 243. |
One of the most efficient engines ever developed operates between 2100 k and 700 k. Its actual efficiency is 40%. What percentage of its maximum possible efficiency is this? |
| A. | 40% |
| B. | 33.30% |
| C. | 60% |
| D. | Pulsejet |
| E. | 66.67% |
| Answer» D. Pulsejet | |
| 244. |
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» F. | |
| 245. |
If the roof of a house is replaced by a shiny metallic surface the temperature inside will |
| A. | microns |
| B. | Decrease |
| C. | Increase |
| D. | Remain unaltered |
| Answer» C. Increase | |
| 246. |
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» B. Separation | |
| 247. |
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» E. A change of state | |
| 248. |
The internal energy of a substance depdnds on |
| A. | Velocity |
| B. | Pressure |
| C. | Entropy |
| D. | Temperature |
| E. | Volume |
| Answer» E. Volume | |
| 249. |
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» C. 47.7 m3/kg mol | |
| 250. |
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» B. the average distance between the molecules of the gas | |