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MCQOPTIONS
This section includes 760 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
_ The function of injector used in small steam plants is to$? |
| A. | Create vacuum in furnace |
| B. | Create vacuum at turbine exhaust |
| C. | Pump feed water |
| D. | Dose chemicals in feed water |
| Answer» D. Dose chemicals in feed water | |
| 452. |
_ In a reaction turbine, when steam flows through the fixed blades,$? |
| A. | Pressure increases while velocity decreases |
| B. | Pressure decreases while velocity increases |
| C. | Pressure and velocity both decreases |
| D. | Pressure and velocity both increases |
| Answer» C. Pressure and velocity both decreases | |
| 453. |
_ When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be$? |
| A. | Choked |
| B. | Under-damping |
| C. | Over-damping |
| D. | None of these |
| Answer» C. Over-damping | |
| 454. |
_ Efficiency of a thermal cycle increases by$? |
| A. | Regeneration |
| B. | Reheating of steam |
| C. | Both (A) and (B) |
| D. | Cooling of steam |
| Answer» D. Cooling of steam | |
| 455. |
_ The water tubes in a Babcock and Wilcox boiler are$? |
| A. | Horizontal |
| B. | Vertical |
| C. | Inclined |
| D. | Horizontal and inclined |
| Answer» D. Horizontal and inclined | |
| 456. |
_ In locomotive boiler, maximum steam pressure is limited to$? |
| A. | 1 kg/cm² |
| B. | 5 kg/cm² |
| C. | 10 kg/cm² |
| D. | 18 kg/cm² |
| Answer» E. | |
| 457. |
_ Boiler stays are used to$? |
| A. | Prevent flat surfaces under pressure from tearing apart |
| B. | Take care of failure in shear |
| C. | Take care of failure in compression |
| D. | Provide support for boiler |
| Answer» B. Take care of failure in shear | |
| 458. |
_ The diameter of internal flue tubes in a Lancashire boiler compared to its shell is$? |
| A. | One-half |
| B. | One-third |
| C. | Two-fourth |
| D. | Two-fifth |
| Answer» E. | |
| 459. |
_ Degree of reaction is defined as the ratio of$? |
| A. | Heat drop in fixed blades to the heat drop in moving blades |
| B. | Heat drop in moving blades to the heat drop in fixed blades |
| C. | Heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades |
| D. | Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades |
| Answer» D. Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades | |
| 460. |
_ The Parsons' reaction turbine has$? |
| A. | Only moving blades |
| B. | Only fixed blades |
| C. | Identical fixed and moving blades |
| D. | Fixed and moving blades of different shape |
| Answer» D. Fixed and moving blades of different shape | |
| 461. |
_ If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by$? |
| A. | Throttling calorimeter |
| B. | Separating calorimeter |
| C. | Combined separating and throttling calorimeter |
| D. | Bucket calorimeter |
| Answer» B. Separating calorimeter | |
| 462. |
_ The equivalent evaporation of a boiler is a measure to compare$? |
| A. | The given boiler with the model |
| B. | The two different boilers of the same make |
| C. | Two different makes of boilers operating under the same operating conditions |
| D. | Any type of boilers operating under any conditions |
| Answer» E. | |
| 463. |
_ For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has$? |
| A. | More heating surface |
| B. | Less heating surface |
| C. | Equal heating surface |
| D. | Heating surface depends on other parameters |
| Answer» B. Less heating surface | |
| 464. |
_ The theoretical indicator diagram of a simple steam engine is based upon the assumption that$? |
| A. | There is no pressure drop due to condensation |
| B. | Steam is admitted at boiler pressure and exhausted at condenser pressure |
| C. | The expansion (or compression) of the steam is hyperbolic |
| D. | All of the above |
| Answer» E. | |
| 465. |
_ For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is$? |
| A. | 1 kg |
| B. | 4/3 kg |
| C. | 8/3 kg |
| D. | 2 kg |
| Answer» C. 8/3 kg | |
| 466. |
_ In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be$? |
| A. | 56 % |
| B. | 63 % |
| C. | 74 % |
| D. | 78 % |
| Answer» C. 74 % | |
| 467. |
_ Pick up the wrong statement about water tube boiler in comparison to fire tube boilers$? |
| A. | Former occupies less space for same power |
| B. | Rate of steam flow is more in former case |
| C. | Former is used for high installed capacity |
| D. | Chances of explosion are less in former case |
| Answer» E. | |
| 468. |
_ In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is$? |
| A. | 0.007 bar |
| B. | 0.053 bar |
| C. | 0.06 bar |
| D. | 0.067 bar |
| Answer» E. | |
| 469. |
_ For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then$? |
| A. | α₁ = α₂ and β₁ = β₂ |
| B. | α₁ = β₁ and α₂= β₂ |
| C. | α₁ < β₁ and α₂ > β₂ |
| D. | α₁ = β₂ and β₁ = α₂ |
| Answer» C. ≈í¬±‚Äö√á√Ö < ≈í‚⧂Äö√á√Ö and ≈í¬±‚Äö√á√á > ≈í‚⧂Äö√á√á | |
| 470. |
_ Fire tube boilers are limited to a maximum design working pressure of$? |
| A. | 1 kg/cm |
| B. | 6 kg/cm |
| C. | 17 kg/cm² |
| D. | 100 kg/cm² |
| Answer» D. 100 kg/cm¬¨‚⧠| |
| 471. |
_ The safety valve on boiler drum compared to safety valve on superheater is set at$? |
| A. | Same value |
| B. | Higher value |
| C. | Lower value |
| D. | Lower/higher depending on steam flow |
| Answer» C. Lower value | |
| 472. |
_ The specific volume of steam with increase in pressure decreases$? |
| A. | Linearly |
| B. | Slowly first and then rapidly |
| C. | Rapidly first and then slowly |
| D. | Inversely |
| Answer» D. Inversely | |
| 473. |
_ The latent heat of steam with increase of pressure$? |
| A. | Remain same |
| B. | Increases |
| C. | Decreases |
| D. | Behaves unpredictably |
| Answer» D. Behaves unpredictably | |
| 474. |
_ Boilers, Engines, Nozzles and Turbines Objective Questions and Answers pdf:- 101. The difference between cornish boiler and lancashire boiler is that$? |
| A. | former is fire tube type and latter is water tube type boiler |
| B. | former is water tube type and latter is fire tube type |
| C. | former contains one fire tube and latter contains two fire tubes |
| D. | none of the above |
| Answer» D. none of the above | |
| 475. |
_ Sulphur content of fuels is very important to the plant operators because it$? |
| A. | Has high heating value |
| B. | Retards electric precipitation |
| C. | Promotes complete combustion |
| D. | Has highly corrosive effect |
| Answer» E. | |
| 476. |
__A nozzle is said to be a divergent nozzle__ |
| A. | When the cross-section of the nozzle increases continuously from entrance to exit |
| B. | When the cross-section of the nozzle decreases continuously from entrance to exit |
| C. | When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit |
| D. | None of the above |
| Answer» B. When the cross-section of the nozzle decreases continuously from entrance to exit | |
| 477. |
__The heat balance sheet for the boiler shows the__ |
| A. | Complete account of heat supplied by 1 kg of dry fuel and the heat consumed |
| B. | Moisture present in the fuel |
| C. | Steam formed by combustion of hydrogen per kg of fuel |
| D. | All of the above |
| Answer» B. Moisture present in the fuel | |
| 478. |
__The average operating pressure of Benson boiler is__ |
| A. | 100 bar |
| B. | 150 bar |
| C. | 200 bar |
| D. | 250 bar |
| Answer» E. | |
| 479. |
__The high pressure and low pressure cylinders in a Tandem type compound engine are regarded as having cranks__ |
| A. | 180° to each other |
| B. | 90° to each other |
| C. | 0° to each other |
| D. | None of these |
| Answer» D. None of these | |
| 480. |
__The working pressure range for a LaMont boiler is__ |
| A. | 0.5 to 10 MN/m² |
| B. | 1 to 15 MN/m² |
| C. | 2.5 to 15 MN/m² |
| D. | 3.5 to 20 MN/m² |
| Answer» E. | |
| 481. |
__The behavior of coal in a furnace is determined by__ |
| A. | The content of sulphur |
| B. | The content of ash and heating value |
| C. | The proximate analysis |
| D. | The exact analysis |
| Answer» D. The exact analysis | |
| 482. |
__The relative heat absorption for successively added equal areas of boiler convection heating surfaces__ |
| A. | Increases |
| B. | Decreases |
| C. | Remain unaffected |
| D. | First increases and then decreases |
| Answer» C. Remain unaffected | |
| 483. |
__Thermal equilibrium means that the flow of steam is__ |
| A. | Isothermal |
| B. | Isentropic |
| C. | Hyperbolic |
| D. | Polytropic |
| Answer» C. Hyperbolic | |
| 484. |
__Duplex feed pumps are used in small steam boilers. These operate on the principle of__ |
| A. | Centrifugal pump |
| B. | Axial flow pump |
| C. | Gear pump |
| D. | Reciprocating pump |
| Answer» E. | |
| 485. |
__The principal function of a stop valve is to__ |
| A. | Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required |
| B. | Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler |
| C. | Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit |
| D. | Increase the temperature of saturated steam without raising its pressure |
| Answer» B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler | |
| 486. |
__In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is__ |
| A. | Low |
| B. | Very low |
| C. | High |
| D. | Very high |
| Answer» E. | |
| 487. |
__The temperature of flue gases at air heater outlet should be__ |
| A. | 100°C |
| B. | Above dew point temperature of flue gases |
| C. | Below dew point temperature of flue gases |
| D. | Less than wet bulb temperature of flue gases |
| Answer» C. Below dew point temperature of flue gases | |
| 488. |
__Equivalent evaporation of water is the evaporation for a feed water supply at 100°C__ |
| A. | And its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm² |
| B. | And its corresponding conversion into dry steam at desired boiler pressure |
| C. | Conversion into steam at atmospheric condition |
| D. | Conversion into steam at the same pressure at which feed water is supplied |
| Answer» B. And its corresponding conversion into dry steam at desired boiler pressure | |
| 489. |
__The ratio of brake power to the indicated power is known as__ |
| A. | Mechanical efficiency |
| B. | Overall efficiency |
| C. | Indicated thermal efficiency |
| D. | Brake thermal efficiency |
| Answer» B. Overall efficiency | |
| 490. |
__In reaction turbines, the axial thrust is due to__ |
| A. | Pressure drop across the rotor |
| B. | Change in axial velocity |
| C. | Both (A) and (B) |
| D. | None of these |
| Answer» D. None of these | |
| 491. |
__Cochran boiler is a__ |
| A. | Horizontal fire tube boiler |
| B. | Horizontal water tube boiler |
| C. | Vertical water tube boiler |
| D. | Vertical fire tube boiler |
| Answer» E. | |
| 492. |
__The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ numbers of stages are required.__ |
| A. | More |
| B. | Less |
| C. | Equal |
| D. | None of these |
| Answer» C. Equal | |
| 493. |
__The basic job of feed water treatment in boilers is to overcome the problem of__ |
| A. | Corrosion |
| B. | Scale |
| C. | Carryover |
| D. | All of the above |
| Answer» E. | |
| 494. |
__The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become__ |
| A. | Wet |
| B. | Superheated |
| C. | Remain dry saturated |
| D. | Dry |
| Answer» B. Superheated | |
| 495. |
__The diameters of fire tubes and superheater tubes in locomotive boiler are__ |
| A. | 47.5 mm, 130 mm |
| B. | 32.5 mm, 180 mm |
| C. | 65.5 mm, 210 mm |
| D. | 24.5 mm, 65 mm |
| Answer» B. 32.5 mm, 180 mm | |
| 496. |
__Sulphur in coal results in__ |
| A. | Corroding air heaters |
| B. | Spontaneous combustion during coal storage |
| C. | Facilitating ash precipitation |
| D. | All of the above |
| Answer» E. | |
| 497. |
__Steam exhaust from high pressure turbine is reheated in__ |
| A. | Boiler drums |
| B. | Superheater tubes |
| C. | Economizer |
| D. | A separate coil located in convection path |
| Answer» E. | |
| 498. |
__The pressure of reheat steam after passing through reheater compared to inlet condition is__ |
| A. | More |
| B. | Less |
| C. | Equal |
| D. | May be more or less depending on capacity of reheater |
| Answer» C. Equal | |
| 499. |
__A safety valve in a locomotive starts leaking. The leaking medium will be__ |
| A. | Water |
| B. | Dry steam |
| C. | Wet steam |
| D. | Super heated steam |
| Answer» E. | |
| 500. |
__Water at pressure of 4 kg/cm² and 160°C temperature when exposed to atmosphere will__ |
| A. | Boil |
| B. | Flash i.e. get converted into steam |
| C. | Remain as it was |
| D. | Cool down |
| Answer» C. Remain as it was | |