MCQOPTIONS
Saved Bookmarks
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.
| 401. |
Determine the specific volume of R-134a at 1 MPa and 50°C, using ideal gas equation of state. |
| A. | 0.022325 m3/kg |
| B. | 0.024325 m3/kg |
| C. | 0.025325 m3/kg |
| D. | 0.026325 m3/kg |
| Answer» C. 0.025325 m3/kg | |
| 402. |
In the reversible polytropic process the value of exponent n varies between |
| A. | 0.2 to 1 |
| B. | 1.0 to 1.2 |
| C. | 1.2 to 1.4 |
| D. | 1.4 to 2.0 |
| Answer» D. 1.4 to 2.0 | |
| 403. |
In an unsaturated air thestate of a vapour is |
| A. | wet |
| B. | superheated |
| C. | saturated |
| D. | unsaturated |
| Answer» C. saturated | |
| 404. |
As differentials, heat & work would bedescribed mathematically as |
| A. | exact |
| B. | inexact |
| C. | point function |
| D. | discontinuity |
| Answer» C. point function | |
| 405. |
Most of the fossil fuelbased power plants operate on |
| A. | rankine cycle |
| B. | brayton cycle |
| C. | carnot cycle |
| D. | either rankine or brayton cycle |
| Answer» E. | |
| 406. |
For any irreversible process the netentropy change is |
| A. | zero |
| B. | positive |
| C. | negative |
| D. | infinite |
| Answer» C. negative | |
| 407. |
Net Work output of the plant with reheat. |
| A. | decreases |
| B. | increases |
| C. | remains same |
| D. | none of the mentioned |
| Answer» C. remains same | |
| 408. |
If a heat enine gives an output of 3 kW when the input is 10,000 J/s, then the thermal efficiency of the engine will be |
| A. | 20% |
| B. | 30% |
| C. | 70% |
| D. | 76.7% |
| Answer» C. 70% | |
| 409. |
Exergy is lost due to |
| A. | irreversible heat transfer |
| B. | through finite temperature difference |
| C. | during the process of heat addition |
| D. | all of the mentioned |
| Answer» E. | |
| 410. |
Compressibility factor Z is given by |
| A. | rt/pv |
| B. | pv/rt |
| C. | (rt/pv)2 |
| D. | (pv/rt)2 |
| Answer» C. (rt/pv)2 | |
| 411. |
Charle's law states that if any gas is heated at constant pressure, its volume |
| A. | changes directly as it absolute temperature |
| B. | changes inversely as its absolute temperature |
| C. | changes as square of the absolute temperature |
| D. | does not change with absolute temperature |
| Answer» B. changes inversely as its absolute temperature | |
| 412. |
In an constant pressure heating certain fraction of heat supplied is converted into work. If ?=1.4 this fraction is |
| A. | 0.25 |
| B. | 0.286 |
| C. | 0.3 |
| D. | 0.327 |
| Answer» E. | |
| 413. |
In a cyclic heat engine operating between a source temperature of 600°C & a sink temperature of 20°C, the least rate of heat rejection per kW net output of theengine is |
| A. | 0.460 kw |
| B. | 0.505 kw |
| C. | 0.588 kw |
| D. | 0.650 kw |
| Answer» C. 0.588 kw | |
| 414. |
An isolated system |
| A. | is a specified region where transfer of energy and/or mass take place |
| B. | is a region of constant mass & only energy is allowed to cross the boundaries |
| C. | cannot transfer either energy or mass to or from the surroundings |
| D. | is one in which mass within the system is not necessarily constant |
| Answer» D. is one in which mass within the system is not necessarily constant | |
| 415. |
In a reheat Rankine cycle steam with enthalpy of 3300 kJ/kg is expanded inh.p turbine to a state where enthalpy is 2650 kJ/kg. The steam is further expnaded from a state where enthalpy is 2950 kJ/kg to enthalpy of 2525 kJ/kg & latent heat of 2201 kJ.kg. The work of the cycle & amount of reheat respectively are |
| A. | 1075 kj/kg,300 kj.kg |
| B. | 1399 kj/kg, 300 kj/kg |
| C. | 1075 kj/kg, 324 kj/kg |
| D. | 1399 kj/kg, 324 kj/kg |
| Answer» B. 1399 kj/kg, 300 kj/kg | |
| 416. |
The isotherm passing through the critical point is called the critical isotherm. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 417. |
Which of the following processes is very close to reversible |
| A. | lifting of a body above the ground |
| B. | compression of a gas in the cylinder against a piston |
| C. | flow of a fluid in a pipe |
| D. | motion of a boat in water |
| Answer» D. motion of a boat in water | |
| 418. |
Correlate the following statements i) the volume of water into which steam is condensed in condenser is very much smaller than the volume of steam before condensationii) the net work of a Rankine cycle is heat supplied in boiler - heat rejected to condenser - pump work |
| A. | both i) & ii) are correct, i) is the correct reason for ii) |
| B. | i) & ii) are correct, ii) is the correct interpretation if i) |
| C. | both i) & ii) are not correct |
| D. | both i) & ii) are independently correct |
| Answer» E. | |
| 419. |
Which of the following is a reversibleprocess? |
| A. | throttling |
| B. | combustion |
| C. | free expansion |
| D. | extension &compression of a spring |
| Answer» E. | |
| 420. |
For the general case, we can write |
| A. | s2-s1<=dq/t for a path |
| B. | s2-s1>=dq/t for a path |
| C. | s2-s1≠dq/t for a path |
| D. | none of the mentioned |
| Answer» C. s2-s1≠dq/t for a path | |
| 421. |
The property of a working substance which increases or decreases as the heat is supplied or removed in a reversiblemanner is known as |
| A. | enthalpy |
| B. | internal energy |
| C. | entropy |
| D. | external energy |
| Answer» D. external energy | |
| 422. |
Which one of the following pairs best expresses a relationship similar to that expressed in the pair 'pressure-volume' for a thermodynamic system undergoinga process? |
| A. | enthalpy-entropy |
| B. | pressure-enthalpy |
| C. | pressure-temperature |
| D. | temperature-entropy |
| Answer» E. | |
| 423. |
First law of thermodynamics gives relationship between which of thefollowing? |
| A. | heat & internal energy |
| B. | heat & work |
| C. | heat, work & properties of the system |
| D. | various thermodynamics processes |
| Answer» D. various thermodynamics processes | |
| 424. |
Steam enters the turbine at 5.44 bar with dryness fraction of 0.9 & is expanded adiabatically to a pressure of 0.68 bar. It will enter the condenser with a quality very close to |
| A. | 0.79 |
| B. | 0.815 |
| C. | 0.84 |
| D. | 0.86 |
| Answer» C. 0.84 | |
| 425. |
The superheat or degree of superheat is given by |
| A. | difference between the temperature of saturated liquid and saturation temperature |
| B. | difference between the temperature of superheated vapour and saturation temperature |
| C. | sum of the temperature of superheated vapour and saturation temperature |
| D. | none of the mentioned |
| Answer» C. sum of the temperature of superheated vapour and saturation temperature | |
| 426. |
Air expands from initial condition of p1, v1 to final condition of 1/2 p1, 2v1.Choose the correct statement |
| A. | no work is performed during expansion |
| B. | expansion is isothermal |
| C. | expansion is polytropic with n= 1.2 |
| D. | expansion is adiabatic |
| Answer» D. expansion is adiabatic | |
| 427. |
Which of the following statements is correct according to Clausius statement of second law of thermodynamics? |
| A. | it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature |
| B. | it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source |
| C. | it is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle |
| D. | none of the above |
| Answer» C. it is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle | |
| 428. |
A heat engine is supplied with 250 kJ/s of heat at a constant fixed temperature of 227°C. The heat is rejected at 27°C. The cycle is reversible, if the amount of heat rejected is |
| A. | 273 kj/s |
| B. | 200 kj/s |
| C. | 180 kj/s |
| D. | 150 kj/s |
| Answer» E. | |
| 429. |
The complete conversion of heat into shaft- work is impossible. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 430. |
If a gas is heated against a pressure, keeping the volume constant, then work done will be equal to |
| A. | ve |
| B. | ve |
| C. | ero |
| D. | nywhere between zero and infinity |
| Answer» D. nywhere between zero and infinity | |
| 431. |
When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel. |
| A. | tomization |
| B. | arbonization |
| C. | ombustion |
| D. | one of these |
| Answer» C. ombustion | |
| 432. |
The smallest quantity of a substance, which can exist by itself in a chemically recognizable form is known as |
| A. | lement |
| B. | ompound |
| C. | tom |
| D. | olecule |
| Answer» E. | |
| 433. |
According to which law, all perfect gases change in volume by 1/273th of their original volume at 0°C for every 1°C change in temperature when pressure remains constant |
| A. | oule's law |
| B. | oyle's law |
| C. | ay Lussac’s law |
| D. | harles' law |
| Answer» E. | |
| 434. |
The absolute zero pressure will be |
| A. | hen molecular momentum of the system becomes zero |
| B. | t sea level |
| C. | t the temperature of - 273 K |
| D. | t the center of the earth |
| Answer» B. t sea level | |
| 435. |
The temperature at which the volume of a gas becomes zero is called |
| A. | bsolute scale of temperature |
| B. | bsolute zero temperature |
| C. | bsolute temperature |
| D. | one of these |
| Answer» C. bsolute temperature | |
| 436. |
All perfect gases change in volume by 1/273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called |
| A. | oyle's law |
| B. | harles' law |
| C. | ay-Lussac law |
| D. | oule's law |
| Answer» C. ay-Lussac law | |
| 437. |
The condition for the reversibility of a cycle is |
| A. | he pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process |
| B. | ll the processes, taking place in the cycle of operation, must be extremely slow |
| C. | he working parts of the engine must be friction free |
| D. | ll of the above |
| Answer» E. | |
| 438. |
An open system is one in which |
| A. | ass does not cross boundaries of the system, though energy may do so |
| B. | either mass nor energy crosses the boundaries of the system |
| C. | oth energy and mass cross the boundaries of the system |
| D. | ass crosses the boundary but not the energy |
| Answer» D. ass crosses the boundary but not the energy | |
| 439. |
A path 1-2-3 is given. A system absorbs 100 kJ as heat and does 60 kJ of work while along the path 1-4-3, it does 20 kJ of work. The heat absorbed during the cycle 1-4-3 is |
| A. | 140 kJ |
| B. | 80 kJ |
| C. | 40 kJ |
| D. | 60 kJ |
| Answer» E. | |
| 440. |
In a no flow reversible process for which p = (-3V + 15) × 105 N/m², V changes from 1 m3 to 2 m3. The work done will be about |
| A. | 00 × 10⁵ joules |
| B. | × 10⁵ joules |
| C. | 0 × 10⁵ joules |
| D. | 0 × 10⁵ kilo joules |
| Answer» D. 0 × 10⁵ kilo joules | |
| 441. |
The distillation carried out in such a way that the liquid with the lowest boiling point is first evaporated and re-condensed, then the liquid with the next higher boiling point is then evaporated and re-condensed, and so on until all the available liquid fuels are separately recovered in the sequence of their boiling points. Such a process is called |
| A. | racking |
| B. | ractional distillation |
| C. | ull distillation |
| D. | arbonisation |
| Answer» C. ull distillation | |
| 442. |
A mixture of gas expands from 0.03 m3 to 0.06 m3 at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is |
| A. | 0 kJ |
| B. | 4 kJ |
| C. | 4 kJ |
| D. | 14 kJ |
| Answer» D. 14 kJ | |
| 443. |
The heat supplied to the gas at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 - T1 = Rise in temperature, and R = Gas constant) |
| A. | R (T2 - T1) |
| B. | cv (T2 - T1) |
| C. | cp (T2 - T1) |
| D. | cp (T2 + T1) |
| Answer» C. cp (T2 - T1) | |
| 444. |
To convert volumetric analysis to gravimetric analysis, the relative volume of each constituent of the flue gases is |
| A. | ivided by its molecular weight |
| B. | ultiplied by its molecular weight |
| C. | ultiplied by its density |
| D. | ultiplied by its specific weight |
| Answer» C. ultiplied by its density | |
| 445. |
Which of the following parameters is constant for a mole for most of the gases at a given temperature and pressure |
| A. | nthalpy |
| B. | olume |
| C. | ass |
| D. | ntropy |
| Answer» C. ass | |
| 446. |
One reversible heat engine operates between 1600 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then temperature T2 is equal to |
| A. | 00 K |
| B. | 000 K |
| C. | 200 K |
| D. | 400 K |
| Answer» B. 000 K | |
| 447. |
An open cycle gas turbine works on |
| A. | Otto cycle |
| B. | Carnot cycle |
| C. | Joule's cycle |
| D. | Stirling cycle |
| Answer» D. Stirling cycle | |
| 448. |
The mass of flue gas per kg of fuel is the ratio of the |
| A. | Mass of oxygen in 1 kg of flue gas to the mass of oxygen in 1 kg of fuel |
| B. | Mass of oxygen in 1 kg of fuel to the mass of oxygen in 1 kg of flue gas |
| C. | Mass of carbon in 1 kg of flue gas to the mass of carbon in 1 kg of fuel |
| D. | Mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas |
| Answer» D. Mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas | |
| 449. |
For which of the following substances, the internal energy and enthalpy are the functions of temperature only |
| A. | Any gas |
| B. | Saturated steam |
| C. | Water |
| D. | Perfect gas |
| Answer» E. | |
| 450. |
Water contained in a beaker can be made to boil by passing steam through it |
| A. | At atmospheric pressure |
| B. | At a pressure greater than atmospheric pressure |
| C. | Any pressure |
| D. | Not possible |
| Answer» C. Any pressure | |