MCQOPTIONS
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MCQOPTIONS
This section includes 1092 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
A gas expands from initial condition of (p1, v1, T1) to final condition (p2, v1, T2), then according to Charle's law: |
| A. | p1t1=p2t2 |
| B. | p1p2 = t1t2 |
| C. | p1+ t2 = p2 + t1 |
| D. | p1t2 = p2t1 |
| Answer» E. | |
| 202. |
The second law of thermodynamicsdefines |
| A. | heat |
| B. | enthalpy |
| C. | internal energy |
| D. | entropy |
| Answer» E. | |
| 203. |
A process which can be stopped at any stage & reversed so that the system & the surroundings are exactly restored to their initial states is known as |
| A. | thermodynamic process |
| B. | irreversible process |
| C. | reversible process |
| D. | isothermal process |
| Answer» D. isothermal process | |
| 204. |
Maximum amount of work that can be converted into heat in any process |
| A. | depends upon initial & final temperature |
| B. | depends upon how much work is lost in friction |
| C. | is 50% |
| D. | is 100% |
| Answer» C. is 50% | |
| 205. |
For two different paths between same two points, entropy change is |
| A. | depends on path taken |
| B. | different |
| C. | same |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 206. |
Turbine blade efficiencyreduces in a Rankine cycle if |
| A. | heat supply in boiler increases |
| B. | heat supply in boiler decreases |
| C. | condenser pressure decreases |
| D. | condenser pressure increases |
| Answer» D. condenser pressure increases | |
| 207. |
The physical properties of a perfect gas are controlled by which of the followingvariables? |
| A. | volume |
| B. | temperature |
| C. | pressure |
| D. | all of the above |
| Answer» E. | |
| 208. |
The internal energy of a perfect gas is afunction of |
| A. | pressure change &temperature |
| B. | temperature change &specific heat |
| C. | pressure & work supplied |
| D. | temperature |
| Answer» E. | |
| 209. |
The efficiency of an ideal Carnot engine depends on |
| A. | working substance |
| B. | on the temperature of the source only |
| C. | on the temperature of the sink only |
| D. | on the temperatures of both the source & the sink |
| Answer» E. | |
| 210. |
Dryness fraction of steam is defined as |
| A. | mass of water vapour in suspension/(mass of water vapour in suspension+mass of dry steam) |
| B. | mass of dry steam/mass of water vapour in suspension |
| C. | mass of dry steam/(mass of dry steam+mass of water vapour in suspension) |
| D. | mass of water vapour in suspension/mass of dry steam |
| Answer» D. mass of water vapour in suspension/mass of dry steam | |
| 211. |
Which of the following represents the latent heat of vaporization at a particular pressure. |
| A. | hf-hg |
| B. | hg-hf |
| C. | hf+hg |
| D. | none of the mentioned |
| Answer» C. hf+hg | |
| 212. |
The magnitude of Z at a particular pressure and temperature indicates the extent of deviation of the gas from the ideal gas behaviour. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 213. |
The unavailable energy is the product of the lowest temperature of heat rejection and the change of entropy of system during the process of supplying heat. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 214. |
Triple point of a pure substance is a point atwhich |
| A. | solid & vapour exist together |
| B. | solid & liquid exist together |
| C. | liquid & vapour exist together |
| D. | solid, liquid & vapour phases existtogether |
| Answer» E. | |
| 215. |
In an open system, there is a transfer of which of the following quantity? |
| A. | mass |
| B. | energy |
| C. | entropy |
| D. | all of the mentioned |
| Answer» E. | |
| 216. |
Cyclic integral of a property is always |
| A. | zero |
| B. | one |
| C. | infinite value |
| D. | none of the mentioned |
| Answer» B. one | |
| 217. |
When two gases suddenly mix up with each other then resultant entropy of thesystem will |
| A. | remain unaltered |
| B. | decrease |
| C. | increase |
| D. | becomes zero |
| Answer» D. becomes zero | |
| 218. |
First law of thermodynamics deals with conservation of |
| A. | mass |
| B. | momentum |
| C. | energy |
| D. | heat |
| Answer» D. heat | |
| 219. |
For pressure ratio = 1, efficiency = 0, then? |
| A. | reheat is used |
| B. | reheat is not used |
| C. | only reheat is used |
| D. | none of the mentioned |
| Answer» C. only reheat is used | |
| 220. |
Only throttling calorimeter is used for measuring |
| A. | very low dryness fraction upto 0.7 |
| B. | very high dryness fraction upto 0.98 |
| C. | dryness fraction of only low pressure steam |
| D. | dryness fraction ofonly high pressure steam |
| Answer» C. dryness fraction of only low pressure steam | |
| 221. |
When the heat transferred isothermally |
| A. | doesnot, can, without |
| B. | exists, cannot, without |
| C. | exists, can, with |
| D. | none of the mentioned |
| Answer» C. exists, can, with | |
| 222. |
A regenerative Rankine cycle may approach efficiency of a Carnot cycle between sametemperature by |
| A. | reducing heat to condenser |
| B. | reducing volume of steam passed into condenser |
| C. | increasing turbine work |
| D. | adding heat a highest temp. |
| Answer» E. | |
| 223. |
The second TdS equation is |
| A. | tds=cp*dt + t(∂v/∂t)dp |
| B. | tds=cp*dt – t(∂v/∂t)dp |
| C. | tds=cp*dt + t(∂t/∂v)dp |
| D. | tds=cp*dt – t(∂t/∂v)dp |
| Answer» C. tds=cp*dt + t(∂t/∂v)dp | |
| 224. |
A Carnot engine receiving heat at 400K has an efficiency of 25%. The C.O.P. of a Carnot refrigerator working between the same temperature limits is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 225. |
The fact that internal energy of a mixture is equal to the sum of the partial internal energies of the gases can also be applied to properties like H,Cv,Cp,S,F, and G. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 226. |
An ideal gas as compared to a real gas atvery high pressure occupies |
| A. | same volume |
| B. | less volume |
| C. | more volume |
| D. | all of the above |
| Answer» D. all of the above | |
| 227. |
According to Joule’s experiments, |
| A. | heat can be completely converted into work |
| B. | work can be completely converted into heat |
| C. | both heat and work are completely interchangeable |
| D. | all of the mentioned |
| Answer» C. both heat and work are completely interchangeable | |
| 228. |
In a reversible cycle, the source temperature is 227°C & the sink temperature is 27°C. The maximum available work for a heat input of 100 kJwill be |
| A. | 100 kj |
| B. | 60 kj |
| C. | 40 kj |
| D. | 88 kj |
| Answer» D. 88 kj | |
| 229. |
The enthalpy of a system |
| A. | i= internal energy + pv |
| B. | i= internal energy + pdv |
| C. | i= internal energy + vdp |
| D. | i= change in internalenergy + pv |
| Answer» C. i= internal energy + vdp | |
| 230. |
A reversible engine performing as refrigerator has COP=33%. If the same machine operates as engine, its efficiencywill be |
| A. | 67% |
| B. | 33% |
| C. | 75% |
| D. | 37.5% |
| Answer» B. 33% | |
| 231. |
Constant pressure process is also known as |
| A. | isopiestic process |
| B. | isobaric process |
| C. | all of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 232. |
The change in entropy is zero during |
| A. | hyperbolic process |
| B. | constant pressureprocess |
| C. | adiabatic processes |
| D. | polytropic process |
| Answer» D. polytropic process | |
| 233. |
When air passes through silica gel, |
| A. | it absorbs water vapour molecules |
| B. | latent heat of condensation is released |
| C. | dbt of air increases |
| D. | all of the mentioned |
| Answer» E. | |
| 234. |
Universal gas constant is defined as equal to product of the molecular weight of thegas & |
| A. | gas constant |
| B. | specific heat at constant volume |
| C. | specific heat a constant pressure |
| D. | ratio of two specific heats |
| Answer» B. specific heat at constant volume | |
| 235. |
Which of the following processes isreversible process? |
| A. | throttling |
| B. | adiabatic |
| C. | isothermal |
| D. | none of the above |
| Answer» B. adiabatic | |
| 236. |
A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid form and the rest is in the vapour form, determine the pressure in the tank. |
| A. | 60.183 kpa |
| B. | 70.183 kpa |
| C. | 80.183 kpa |
| D. | 90.183 kpa |
| Answer» C. 80.183 kpa | |
| 237. |
For any reversible process, the change in entropy of the system & surroundings is |
| A. | zero |
| B. | unity |
| C. | negative |
| D. | positive |
| Answer» B. unity | |
| 238. |
The equation which forms the basis of the Mollier diagram is |
| A. | tds=-dh+vdp |
| B. | tds=dh+vdp |
| C. | tds=dh-vdp |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 239. |
One reversible heat engine operates between 1600 K & T₂ K & another reversible heat engine operates between T₂ K & 400 K. If both the engines have the temperature T₂ must be equal to |
| A. | 100 kj |
| B. | 1200 k |
| C. | 1400 k |
| D. | 800 k |
| Answer» E. | |
| 240. |
During an adiabatic compression when temperature increase by 100% the pressure increases by 1000%. The ratio ofspecific heats, ? is |
| A. | 1.3 |
| B. | 1.35 |
| C. | 1.4 |
| D. | 1.45 |
| Answer» D. 1.45 | |
| 241. |
Which one of the following statements iscorrect? |
| A. | pressure is an extensiveproperty |
| B. | density is an intensiveproperty |
| C. | density is an extensiveproperty |
| D. | temperature is anextensive property |
| Answer» C. density is an extensiveproperty | |
| 242. |
In above question the heat supplied & efficiency respectively are |
| A. | 3276 kj/kg, 42.7% |
| B. | 2976 kj/kg, 36.12% |
| C. | 3300 kj/kg, 32.6% |
| D. | 330 kj/kg, 42.4% |
| Answer» C. 3300 kj/kg, 32.6% | |
| 243. |
Absolute zero temperature is taken as |
| A. | -273??c |
| B. | 273??c |
| C. | 237??c |
| D. | -373??c |
| Answer» B. 273??c | |
| 244. |
A system comprising a single phase iscalled a |
| A. | closed system |
| B. | open system |
| C. | isolated system |
| D. | homogeneous system |
| Answer» E. | |
| 245. |
Consider the following statements regarding superheating in Rankine Cycles1. It reduces the specific steam consumption2. It increases the dryness fraction of steam at the exhaust for the same value of condenser pressure3. It reduces the cycle efficiency Of the these statements |
| A. | 1 & 2 are correct |
| B. | 2 & 3 are correct |
| C. | 1 & 3 are correct |
| D. | 1, 2 & 3 are correct |
| Answer» B. 2 & 3 are correct | |
| 246. |
Gases could have an infinite number ofspecific heats but only ……. Specific heats are defined |
| A. | one |
| B. | two |
| C. | three |
| D. | four |
| Answer» C. three | |
| 247. |
The gas laws can be usedwith minimum error is case of |
| A. | wet steam |
| B. | dry steam |
| C. | saturated steam |
| D. | superheated steam |
| Answer» E. | |
| 248. |
The lowest practicable temperature of heat rejected is the |
| A. | given temperature |
| B. | 0k |
| C. | temperature of surroundings |
| D. | 273k |
| Answer» D. 273k | |
| 249. |
A sequence of operations which a gas undergoes in such a way that final state issame as original state, mahe a |
| A. | reversible cycle |
| B. | irreversible cycle |
| C. | thermal cycle |
| D. | thermodynamic cycle |
| Answer» E. | |
| 250. |
A Reheat Rankine cycle |
| A. | reduces total heat produced in boiler |
| B. | increases total heat produced in boiler |
| C. | increases volume of steam produced in boiler |
| D. | reduces volume of steam produced inboiler |
| Answer» C. increases volume of steam produced in boiler | |