MCQOPTIONS
Saved Bookmarks
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.
| 701. |
Maximum energy loss in a boiler occurs due to |
| A. | Unburnt carbon in ash |
| B. | Incomplete combustion |
| C. | Ash content |
| D. | Flue gases |
| Answer» E. | |
| 702. |
The basic purpose of drum in boiler is to |
| A. | Serve as storage of steam |
| B. | Serve as storage of feed water for water wall |
| C. | Remove salts from water |
| D. | Separate steam from water |
| Answer» E. | |
| 703. |
Coke is produced by |
| A. | Pulverizing coal in inert atmosphere |
| B. | Heating wood in a limited supply of air at temperatures below 300°C |
| C. | Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel |
| D. | Enriching carbon in the coal |
| Answer» D. Enriching carbon in the coal | |
| 704. |
The diameter of tubes for natural circulation boiler as compared to controlled circulation boilers is |
| A. | More |
| B. | Less |
| C. | Same |
| D. | Could be more or less depending on other factors |
| Answer» B. Less | |
| 705. |
The expansion of steam in a nozzle follows |
| A. | Carnot cycle |
| B. | Rankine cycle |
| C. | Joule cycle |
| D. | Stirling cycle |
| Answer» C. Joule cycle | |
| 706. |
Blow off cock in a boiler is used 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» C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit | |
| 707. |
The bituminous coal is no caking if its carbon content is |
| A. | 78-81% |
| B. | 81-85% |
| C. | 85-90% |
| D. | 90-95% |
| Answer» B. 81-85% | |
| 708. |
In accelerated circulation type boiler |
| A. | Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum |
| B. | Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam |
| C. | Feed pump is employed to supplement natural circulation in water wall type furnace |
| D. | Water is converted into steam in one pass without any recirculation |
| Answer» C. Feed pump is employed to supplement natural circulation in water wall type furnace | |
| 709. |
The critical pressure ratio for gases is |
| A. | 0.528 |
| B. | 0.546 |
| C. | 0.577 |
| D. | 0.582 |
| Answer» B. 0.546 | |
| 710. |
Fire tube boilers are |
| A. | Internally fired |
| B. | Externally fired |
| C. | Internally as well as externally fired |
| D. | None of these |
| Answer» B. Externally fired | |
| 711. |
Mechanical equivalent of heat for 1 kcal or Joule's equivalent is equal to |
| A. | 421 kg.m |
| B. | 421 kg.m |
| C. | 539 kg.m |
| D. | 102 kg.m |
| Answer» B. 421 kg.m | |
| 712. |
The capacity of induced draft fan compared to forced draft fan in a boiler is |
| A. | Same |
| B. | More |
| C. | Less |
| D. | Less or more depending on size of boiler |
| Answer» C. Less | |
| 713. |
The main object of a boiler trial is |
| A. | To determine the generating capacity of the boiler |
| B. | To determine the thermal efficiency of the boiler when working at a definite pressure |
| C. | To prepare heat balance sheet for the boiler |
| D. | All of the above |
| Answer» E. | |
| 714. |
The number of water level indicators in a boiler are generally __________ in number. |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 715. |
The maximum efficiency of a reaction turbine is |
| A. | 2 sin²α/(1 + sin²α) |
| B. | 2 cos²α/(1 + cos²α) |
| C. | (1 + sin²α)/2 sin²α |
| D. | (1 + cos²α)/2 cos²α |
| Answer» C. (1 + sin¬¨‚â§≈í¬±)/2 sin¬¨‚â§≈í¬± | |
| 716. |
Secondary air is the air used to |
| A. | Provide air around burners for obtaining optimum combustion |
| B. | Transport and dry the coal |
| C. | Convert CO (formed in lower zone of furnace) into CO‚ÇÇ at higher zone |
| D. | Air delivered by induced draft fan |
| Answer» B. Transport and dry the coal | |
| 717. |
Calorific value of coal is of the order of |
| A. | 200-400 kcal/ kg |
| B. | 800-1200 kcal/ kg |
| C. | 2000-4000 kcal/ kg |
| D. | 5000-8000 kcal/ kg |
| Answer» D. 5000-8000 kcal/ kg | |
| 718. |
In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will |
| A. | Remain unaffected |
| B. | Improve |
| C. | Worsen |
| D. | May improve/worsen depending on size |
| Answer» D. May improve/worsen depending on size | |
| 719. |
In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be# |
| A. | 160/3 m/s |
| B. | 320/3 m/s |
| C. | 640/3 m/s |
| D. | 640 m/s |
| Answer» D. 640 m/s | |
| 720. |
In forced recirculation type boiler, |
| A. | Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum |
| B. | Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam |
| C. | Feed pump is employed to supplement natural circulation in water wall type furnace |
| D. | Water is converted into steam in one pass without any recirculation |
| Answer» D. Water is converted into steam in one pass without any recirculation | |
| 721. |
Cut-off governing as compared to throttle governing is |
| A. | Less efficient and less economical |
| B. | Less efficient and more economical |
| C. | More efficient and less economical |
| D. | More efficient and more economical |
| Answer» E. | |
| 722. |
A closed vessel made of steel and used for the generation of steam is called a |
| A. | Steam boiler |
| B. | Steam turbine |
| C. | Steam condenser |
| D. | Steam injector |
| Answer» B. Steam turbine | |
| 723. |
The evaporation of 15.653 kg of water per hour from and at 100°C is called# |
| A. | Evaporative capacity |
| B. | Factor of evaporation |
| C. | Equivalent evaporation |
| D. | One boiler h.p. |
| Answer» E. | |
| 724. |
The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle) |
| A. | V = 44.72 hd K |
| B. | V = 44.72 K hd |
| C. | V = 44.72 K hd |
| D. | V = 44.72 K hd |
| Answer» D. V = 44.72 K hd | |
| 725. |
A wet vapor can be completely specified by |
| A. | Pressure only |
| B. | Temperature only |
| C. | Dryness fraction only |
| D. | Pressure and dryness fraction |
| Answer» E. | |
| 726. |
In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts. and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is |
| A. | 40 % |
| B. | 25 % |
| C. | 50 % |
| D. | 80 % |
| Answer» E. | |
| 727. |
The diagram efficiency is the ratio of |
| A. | Workdone on the blades to the energy supplied to the blades |
| B. | Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam |
| C. | Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam |
| D. | None of the above |
| Answer» B. Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam | |
| 728. |
The high steam and low water safety valve is not used in |
| A. | Cochran boiler |
| B. | Cornish boiler |
| C. | Lancashire boiler |
| D. | Locomotive boiler |
| Answer» E. | |
| 729. |
Willian’s line follows the law (where b = A constant representing the shape of the Willian’s line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)# |
| A. | I.P. = a √ó m + b |
| B. | m = a + b √ó I.P. |
| C. | I.P. = b √ó m + a |
| D. | m = (b/I.P.) - a |
| Answer» C. I.P. = b ‚àö√≥ m + a | |
| 730. |
Which of the following compound steam engine requires a smaller flywheel? |
| A. | Receiver type |
| B. | Tandem type |
| C. | Woolf type |
| D. | All of these |
| Answer» B. Tandem type | |
| 731. |
In a glass tube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to |
| A. | Water space also |
| B. | Chimney |
| C. | Steam space |
| D. | Superheater |
| Answer» D. Superheater | |
| 732. |
The value of diagram factor depends upon |
| A. | Initial conditions of steam |
| B. | Back pressure |
| C. | Initial pressure of steam |
| D. | All of these |
| Answer» E. | |
| 733. |
In an impulse reaction turbine, the pressure drops gradually and continuously over |
| A. | Fixed blades |
| B. | Moving blades |
| C. | Both fixed and moving blades |
| D. | None of these |
| Answer» D. None of these | |
| 734. |
The velocity of steam at throat of the nozzle is __________ the velocity of sound. |
| A. | Equal to |
| B. | Less than |
| C. | More than |
| D. | None of these |
| Answer» B. Less than | |
| 735. |
The critical pressure gives the velocity of steam at the throat |
| A. | Equal to the velocity of sound |
| B. | Less than the velocity of sound |
| C. | More than the velocity of sound |
| D. | None of these |
| Answer» B. Less than the velocity of sound | |
| 736. |
In cross compounding, the cylinders are arranged |
| A. | Side by side and each cylinder has common piston, connecting rod and crank |
| B. | Side by side and each cylinder has separate piston, connecting rod and crank |
| C. | At 90° and each cylinder has common piston, connecting rod and crank |
| D. | At 90° and each cylinder has separate piston, connecting rod and crank |
| Answer» C. At 90¬¨‚àû and each cylinder has common piston, connecting rod and crank | |
| 737. |
The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called |
| A. | Safety valve |
| B. | Water level indicator |
| C. | Pressure gauge |
| D. | Fusible plug |
| Answer» B. Water level indicator | |
| 738. |
For the same diameter and thickness of tube, a water tube boiler has ________ heating surface as compared to fire tube boiler. |
| A. | More |
| B. | Less |
| C. | Equal |
| D. | None of these |
| Answer» B. Less | |
| 739. |
Spontaneous combustion is a phenomenon in which |
| A. | All the fuel burns instantaneously producing high energy release |
| B. | Fuel burns with less air |
| C. | Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal |
| D. | Explosion in furnace |
| Answer» D. Explosion in furnace | |
| 740. |
The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called |
| A. | Condenser efficiency |
| B. | Vacuum efficiency |
| C. | Nozzle efficiency |
| D. | Boiler efficiency |
| Answer» B. Vacuum efficiency | |
| 741. |
The critical pressure ratio is given by (where p‚ÇÅ = Initial pressure of steam, and p‚ÇÇ = Pressure of steam at throat or critical pressure)# |
| A. | p‚ÇÅ. p‚ÇÇ |
| B. | p‚ÇÅ/p‚ÇÇ |
| C. | p‚ÇÇ/p‚ÇÅ |
| D. | p‚ÇÅ + p‚ÇÇ |
| Answer» D. p‚Äö√á√Ö + p‚Äö√á√á | |
| 742. |
In a Tandem type compound engine, the high pressure and low pressure cylinders |
| A. | Have common piston rod |
| B. | Are set at 90° |
| C. | Have separate piston rods |
| D. | Are set in V-arrangement |
| Answer» B. Are set at 90¬¨‚àû | |
| 743. |
Fire tube boilers are those in which |
| A. | Flue gases pass through tubes and water around it |
| B. | Water passes through the tubes and flue gases around it |
| C. | Forced circulation takes place |
| D. | Tubes are laid vertically |
| Answer» B. Water passes through the tubes and flue gases around it | |
| 744. |
The expansion of steam, as it flows over the blades in reaction turbine, represents |
| A. | Isothermal process |
| B. | Isentropic process |
| C. | Throttling process |
| D. | Free expansion process |
| Answer» C. Throttling process | |
| 745. |
The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced. |
| A. | Remains same |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» D. None of these | |
| 746. |
Which of the following coals has the highest calorific value? |
| A. | Anthracite coal |
| B. | Bituminous coal |
| C. | Lignite |
| D. | Peat |
| Answer» B. Bituminous coal | |
| 747. |
The effect of bleeding is that |
| A. | It increases the thermodynamic efficiency of the turbine |
| B. | Boiler is supplied with hot water |
| C. | It decreases the power developed by the turbine |
| D. | All of the above |
| Answer» E. | |
| 748. |
In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of |
| A. | 10 atmospheres |
| B. | 20 atmospheres |
| C. | 30 atmospheres |
| D. | 40 atmospheres |
| Answer» C. 30 atmospheres | |
| 749. |
The radius of a dished head is taken approximately as |
| A. | One fourth |
| B. | Half |
| C. | One |
| D. | Two |
| Answer» D. Two | |
| 750. |
The draught in locomotive boilers is produced by a |
| A. | Chimney |
| B. | Centrifugal fan |
| C. | Steam jet |
| D. | None of these |
| Answer» D. None of these | |