MCQOPTIONS
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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.
| 651. |
Relative percentage of heat absorbed through the heat transfer of (i) Furnace water wall (ii) Boiler tank (iii) Superheater (iv) Economizer (v) Air-heater of a typical boiler of 200 MW capacity would be of the order of |
| A. | 48 : 20 : 15 : 7 : 10 |
| B. | 10 : 7 : 15 : 20 : 48 |
| C. | 20 : 48 : 7 : 15 : 10 |
| D. | 7 : 15 : 20 : 10 : 48 |
| Answer» B. 10 : 7 : 15 : 20 : 48 | |
| 652. |
The air pressure at the fuel bed is reduced below that of atmosphere by means of a fan placed at or near the bottom of the chimney to produce a draught. Such a draught is called |
| A. | Natural draught |
| B. | Induced draught |
| C. | Forced draught |
| D. | Balanced draught |
| Answer» C. Forced draught | |
| 653. |
The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by |
| A. | V = 2g H' |
| B. | V = 2g/H' |
| C. | V = H'/2g |
| D. | V = 2gH' |
| Answer» B. V = 2g/H' | |
| 654. |
At critical point, i.e. p=225.65 kg/cm², the latent enthalpy of vaporisation is$ |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Depends on temperature also |
| Answer» D. Depends on temperature also | |
| 655. |
If partial pressure of air and steam be ‘pa’ and ‘ps’ respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to$ |
| A. | ps - pa |
| B. | pa - ps |
| C. | pa + ps |
| D. | None of these |
| Answer» D. None of these | |
| 656. |
Lancashire boiler has __________ internal flue tubes. |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 657. |
The discharge is __________ at critical pressure. |
| A. | Zero |
| B. | Minimum |
| C. | Maximum |
| D. | None of these |
| Answer» D. None of these | |
| 658. |
The high pressure boiler is one, which produces steam at a pressure more than |
| A. | Atmospheric pressure |
| B. | 5 kg/cm² |
| C. | 10 kg/cm² |
| D. | 7580 kg/cm² |
| Answer» E. | |
| 659. |
Parson's reaction turbine is a __________ reaction turbine. |
| A. | 40 percent |
| B. | 50 percent |
| C. | 60 percent |
| D. | 70 percent |
| Answer» C. 60 percent | |
| 660. |
Rateau turbine is |
| A. | Simple reaction turbine |
| B. | Velocity compounded turbine |
| C. | Pressure compounded turbine |
| D. | Pressure-velocity compounded turbine |
| Answer» D. Pressure-velocity compounded turbine | |
| 661. |
Which type of boiler can meet rapid changes of load? |
| A. | Vertical fire tube type |
| B. | Horizontal fire tube type |
| C. | Horizontal water tube type |
| D. | Forced circulation type |
| Answer» E. | |
| 662. |
Which of the following is not a boiler mounting? |
| A. | Blow off cock |
| B. | Feed check valve |
| C. | Economiser |
| D. | Fusible plug |
| Answer» D. Fusible plug | |
| 663. |
The draught may be produced by a |
| A. | Mechanical fan |
| B. | Chimney |
| C. | A steam jet |
| D. | All of these |
| Answer» E. | |
| 664. |
Boiler parameters are expressed by |
| A. | Tonnes/hr. of steam |
| B. | Pressure of steam in kg/cm² |
| C. | Temperature of steam in °C |
| D. | All of the above |
| Answer» E. | |
| 665. |
The function of a cross-head is to guide motion of the _________ and to prevent it from bending. |
| A. | Piston rod |
| B. | Connecting rod |
| C. | Eccentric rod |
| D. | Valve rod |
| Answer» B. Connecting rod | |
| 666. |
Blading efficiency is also known as |
| A. | Stage efficiency |
| B. | Diagram efficiency |
| C. | Nozzle efficiency |
| D. | None of these |
| Answer» C. Nozzle efficiency | |
| 667. |
Pulverized fuel is used for |
| A. | Better burning |
| B. | More calorific value |
| C. | Less radiation loss |
| D. | Medium sized units |
| Answer» B. More calorific value | |
| 668. |
A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly |
| A. | 1.05 |
| B. | 2.86 |
| C. | 6.65 |
| D. | 10.05 |
| Answer» C. 6.65 | |
| 669. |
The friction present between the steam and the nozzle surfaces reduces the heat drop by |
| A. | 10 to 15% |
| B. | 15 to 25% |
| C. | 25 to 40% |
| D. | 40 to 60% |
| Answer» B. 15 to 25% | |
| 670. |
The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be |
| A. | 0.4 |
| B. | 0.56 |
| C. | 0.67 |
| D. | 1.67 |
| Answer» B. 0.56 | |
| 671. |
A compound steam engine in which piston rods of high pressure and low pressure cylinders are attached to two different cranks set at 90° to each other, is called$ |
| A. | Receiver type compound engine |
| B. | Tandem type compound engine |
| C. | Woolf type compound engine |
| D. | Both (A) and (B) |
| Answer» B. Tandem type compound engine | |
| 672. |
The function of a flywheel is |
| A. | To convert reciprocating motion of the piston into rotary motion |
| B. | To convert rotary motion of the crankshaft into to and fro motion of the valve rod |
| C. | To prevent fluctuation of speed |
| D. | To keep the engine speed uniform at all load conditions |
| Answer» D. To keep the engine speed uniform at all load conditions | |
| 673. |
Evaporative capacity of boiler is expressed as |
| A. | kg of steam produced |
| B. | Steam pressure produced |
| C. | kg of fuel fired |
| D. | kg of steam produced per kg of fuel fifed |
| Answer» E. | |
| 674. |
The density of supersaturated steam is about __________ that of the ordinary saturated vapor at the corresponding pressure. |
| A. | Same as |
| B. | 2 times |
| C. | 4 times |
| D. | 8 times |
| Answer» E. | |
| 675. |
The diagram factor is the ratio of the |
| A. | Area of the actual indicator diagram to the area of theoretical indicator diagram |
| B. | Actual workdone per stroke to the theoretical workdone per stroke |
| C. | Actual mean effective pressure to the theoretical mean effective pressure |
| D. | Any one of the above |
| Answer» E. | |
| 676. |
The velocity of whirl at outlet for an axial discharge turbine is |
| A. | Minimum |
| B. | Maximum |
| C. | Zero |
| D. | None of these |
| Answer» D. None of these | |
| 677. |
Alkaline pyrogallate is used in Orsat's apparatus for absorption of |
| A. | CO‚ÇÇ |
| B. | CO |
| C. | O‚ÇÇ |
| D. | N‚ÇÇ |
| Answer» D. N‚Äö√á√á | |
| 678. |
The power of a boiler may be defined as |
| A. | The ratio of heat actually used in producing the steam to the heat liberated in the furnace |
| B. | The amount of water evaporated or steam produced in kg per kg of fuel burnt |
| C. | The amount of water evaporated from and at 100° C into dry and saturated steam |
| D. | The evaporation of 15.653 kg of water per hour from and at 100° C |
| Answer» C. The amount of water evaporated from and at 100¬¨‚àû C into dry and saturated steam | |
| 679. |
The stage efficiency (ηS) is given by (where ηB = Blading efficiency, and ηN = Nozzle efficiency)$ |
| A. | ηS = ηB × ηN |
| B. | ηS = ηB / ηN |
| C. | ηS = ηN / ηB |
| D. | None of these |
| Answer» B. ≈í‚àëS = ≈í‚àëB / ≈í‚àëN | |
| 680. |
The economiser is used in boilers to |
| A. | Increase thermal efficiency of boiler |
| B. | Economize on fuel |
| C. | Extract heat from the exhaust flue gases |
| D. | Increase flue gas temperature |
| Answer» B. Economize on fuel | |
| 681. |
A device used to heat feed water by utilizing the heat in me exhaust flue gases before leaving through the chimney, is known as |
| A. | Economizer |
| B. | Fusible plug |
| C. | Superheater |
| D. | Stop valve |
| Answer» B. Fusible plug | |
| 682. |
Efficiency of Rankine cycle can be increased by |
| A. | Decreasing initial steam pressure and temperature |
| B. | Increasing exhaust pressure |
| C. | Decreasing exhausts pressure |
| D. | Increasing the expansion ratio |
| Answer» B. Increasing exhaust pressure | |
| 683. |
With increase in load, convection superheater has |
| A. | Drooping characteristic |
| B. | Linear characteristic |
| C. | Rising characteristic |
| D. | Flat characteristic |
| Answer» D. Flat characteristic | |
| 684. |
The ratio of the actual vacuum to the ideal vacuum in a condenser is called |
| A. | Condenser efficiency |
| B. | Vacuum efficiency |
| C. | Nozzle efficiency |
| D. | Boiler efficiency |
| Answer» C. Nozzle efficiency | |
| 685. |
Steam engine operates on |
| A. | Carnot cycle |
| B. | Joule cycle |
| C. | Stirling cycle |
| D. | Brayton cycle |
| Answer» E. | |
| 686. |
Which of the following is steam dial? |
| A. | Non-coking bituminous coal |
| B. | Brown coal |
| C. | Pulverized coal |
| D. | Coking bituminous coal |
| Answer» B. Brown coal | |
| 687. |
On Millier chart, the constant pressure lines |
| A. | Diverge from left to right |
| B. | Diverge from right to left |
| C. | Are equally spaced throughout |
| D. | First rise up and then fall |
| Answer» B. Diverge from right to left | |
| 688. |
Cut-off ratio is the ratio of |
| A. | Swept volume to the volume at cut-off |
| B. | Volume at cut-off to the clearance volume |
| C. | Volume at cut-off to the swept volume |
| D. | Clearance volume to the volume at cut-off |
| Answer» D. Clearance volume to the volume at cut-off | |
| 689. |
In a reaction turbine, when steam flows through the moving 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» D. Pressure and velocity both increases | |
| 690. |
When the speed of the crankshaft is between 100 r.p.m. and 250 r.p.m., the engine said to be a |
| A. | Slow speed engine |
| B. | Medium speed steam engine |
| C. | High speed steam engine |
| D. | None of these |
| Answer» C. High speed steam engine | |
| 691. |
In locomotives, the draught is produced by |
| A. | Chimney |
| B. | Induced draft fan |
| C. | Both combined (A) and (B) |
| D. | Steam jet draught |
| Answer» E. | |
| 692. |
The major axis of elliptical manholes on the shell should be provided |
| A. | Longitudinally |
| B. | Circumferentially |
| C. | On dished end |
| D. | Anywhere |
| Answer» C. On dished end | |
| 693. |
A single acting steam engine produces __________ power than that of double acting steam engine. |
| A. | Equal |
| B. | Half |
| C. | Double |
| D. | Four times |
| Answer» C. Double | |
| 694. |
A fusible plug is fitted in small boilers in order to |
| A. | Avoid excessive build up of pressure |
| B. | Avoid explosion |
| C. | Extinguish fire if water level in the boiler falls below alarming limit |
| D. | Control steam dome |
| Answer» D. Control steam dome | |
| 695. |
On Mollier chart, flow through turbine is represented by |
| A. | Horizontal straight line |
| B. | Vertical straight line |
| C. | Straight inclined line |
| D. | Curved line |
| Answer» C. Straight inclined line | |
| 696. |
A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as |
| A. | Blow off cock |
| B. | Fusible plug |
| C. | Superheater |
| D. | Stop valve |
| Answer» E. | |
| 697. |
The length of Lancashire boiler varies from |
| A. | 5 to 6 m |
| B. | 6 to 7 m |
| C. | 7.25 to 9 m |
| D. | 9 to 10 m |
| Answer» D. 9 to 10 m | |
| 698. |
During polytropic process |
| A. | Heat transfer takes place across cylinder walls |
| B. | Work is done |
| C. | Steam may be wet, dry or superheated after expansion |
| D. | All of the above |
| Answer» E. | |
| 699. |
The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle) |
| A. | Remains constant |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» B. Decreases | |
| 700. |
Heating value of fuel used is as on fired basis. If it is reported for dry or moisture free fuel, then latter should be multiplied by the following factor to correct for as fired value |
| A. | (1- moisture content) |
| B. | (1 + moisture content) |
| C. | 1 + moisture content |
| D. | 1 – moisture content |
| Answer» B. (1 + moisture content) | |