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.
| 251. |
Water 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. | Work is done during adiabatic expansion |
| D. | Change in enthalpy |
| Answer» D. Change in enthalpy | |
| 252. |
In a compound steam engine, the first stage of expansion is carried out in a high pressure cylinder whereas the last expansion is completed in low pressure cylinder. The diameter of high pressure cylinder is _________ the low pressure cylinder.%! |
| A. | Equal to |
| B. | Less than |
| C. | More than |
| D. | None of these |
| Answer» C. More than | |
| 253. |
The effect of friction in the nozzle __________ dryness fraction of steam.%! |
| A. | Has no effect on |
| B. | Decreases |
| C. | Increases |
| D. | None of these |
| Answer» D. None of these | |
| 254. |
A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as%! |
| A. | Steam condenser |
| B. | Steam boiler |
| C. | Steam preheater |
| D. | Economiser |
| Answer» B. Steam boiler | |
| 255. |
Size of boiler tubes is specified by%! |
| A. | Mean diameter and thickness |
| B. | Inside diameter and thickness |
| C. | Outside diameter and thickness |
| D. | Outside diameter and inside diameter |
| Answer» D. Outside diameter and inside diameter | |
| 256. |
The diameter of Cornish boiler is of the order of%! |
| A. | 12 m |
| B. | 1.52.5 m |
| C. | 23 m |
| D. | 2.53.5 m |
| Answer» B. 1.52.5 m | |
| 257. |
Primary 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 forced draft fan |
| Answer» C. Convert CO (formed in lower zone of furnace) into CO‚Äö√á√á at higher zone | |
| 258. |
In a nozzle, the effect of super-saturation is to%! |
| A. | Decrease dryness fraction of steam |
| B. | Decrease specific volume of steam |
| C. | Increase the entropy |
| D. | Increase the heat drop |
| Answer» D. Increase the heat drop | |
| 259. |
The water tubes in a simple vertical boiler are%! |
| A. | Horizontal |
| B. | Vertical |
| C. | Inclined |
| D. | None of these |
| Answer» D. None of these | |
| 260. |
The ratio of the isentropic heat drop to the heat supplied, is called%! |
| A. | Reheat factor |
| B. | Stage efficiency |
| C. | Internal efficiency |
| D. | Rankine efficiency |
| Answer» E. | |
| 261. |
Water tube boilers are%! |
| A. | Internally fired |
| B. | Externally fired |
| C. | Internally as well as externally fired |
| D. | None of these |
| Answer» C. Internally as well as externally fired | |
| 262. |
Which of the following is required for a steam condensing plant?%! |
| A. | Condenser |
| B. | Condensate pump |
| C. | Air extraction pump |
| D. | All of these |
| Answer» E. | |
| 263. |
The maximum discharge through a chimney occurs when the height of chimney is%! |
| A. | Infinitely long |
| B. | Around 200 meters |
| C. | Equal to the height of the hot gas column producing draught |
| D. | Outside temperature is very low |
| Answer» D. Outside temperature is very low | |
| 264. |
An economiser in a boiler%! |
| A. | Increases steam pressure |
| B. | Increases steam flow |
| C. | Decreases fuel consumption |
| D. | Decreases steam pressure |
| Answer» D. Decreases steam pressure | |
| 265. |
A binary vapor plant consists of%! |
| A. | Steam turbine |
| B. | Steam condenser |
| C. | Mercury boiler |
| D. | All of these |
| Answer» E. | |
| 266. |
The ultimate analysis of fuel lists%! |
| A. | Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume |
| B. | Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight |
| C. | Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash |
| D. | Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash |
| Answer» C. Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash | |
| 267. |
A _________ in a boiler is used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit.%! |
| A. | Blow off cock |
| B. | Fusible plug |
| C. | Stop valve |
| D. | Safety valve |
| Answer» C. Stop valve | |
| 268. |
The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as%! |
| A. | Regenerative heating |
| B. | Reheating of steam |
| C. | Bleeding |
| D. | None of these |
| Answer» D. None of these | |
| 269. |
The fusible plug in small boilers is located%! |
| A. | In the drum |
| B. | In the fire tubes |
| C. | Above steam dome |
| D. | Over the combustion chamber |
| Answer» E. | |
| 270. |
The diameter of superheated tubes in a locomotive boiler is%! |
| A. | 13 mm |
| B. | 31 mm |
| C. | 130 mm |
| D. | 230 mm |
| Answer» D. 230 mm | |
| 271. |
When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.%! |
| A. | Increases |
| B. | Decreases |
| C. | Remain same |
| D. | None of these |
| Answer» C. Remain same | |
| 272. |
Lancashire boiler is used where working pressure and power required are%! |
| A. | Low |
| B. | Moderate |
| C. | High |
| D. | None of these |
| Answer» C. High | |
| 273. |
The Locomotive boiler has%! |
| A. | 137 fire tubes and 44 superheated tubes |
| B. | 147 fire tubes and 34 superheated tubes |
| C. | 157 fire tubes and 24 superheated tubes |
| D. | 167 fire tubes and 14 superheated tubes |
| Answer» D. 167 fire tubes and 14 superheated tubes | |
| 274. |
The state of vapor under saturation condition is described by%! |
| A. | Pressure alone |
| B. | Temperature alone |
| C. | Pressure and temperature |
| D. | Pressure and dryness fraction |
| Answer» E. | |
| 275. |
The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as%! |
| A. | Equivalent evaporation |
| B. | Factor of evaporation |
| C. | Boiler efficiency |
| D. | Power of a boiler |
| Answer» D. Power of a boiler | |
| 276. |
An ideal regenerative cycle is%! |
| A. | Equal to Carnot cycle |
| B. | Less than Carnot cycle |
| C. | More than Carnot cycle |
| D. | Could be anything |
| Answer» C. More than Carnot cycle | |
| 277. |
The height of chimney in a power plant is governed by%! |
| A. | The draft to be created |
| B. | Limitation of construction facilities |
| C. | Control of pollution |
| D. | Quantity of flue gases to be handled |
| Answer» D. Quantity of flue gases to be handled | |
| 278. |
Fusible plug for boilers is made of fusible metal containing tin, lead, and%! |
| A. | Bismuth |
| B. | Copper |
| C. | Aluminium |
| D. | Nickel |
| Answer» B. Copper | |
| 279. |
Expansion ratio is the ratio of%! |
| A. | Swept volume to the volume at cut-off |
| B. | Clearance volume to the swept volume |
| C. | Volume at cut-off to the swept volume |
| D. | Swept volume to the clearance volume |
| Answer» B. Clearance volume to the swept volume | |
| 280. |
The function of a valve rod is%! |
| A. | To provide reciprocating motion to the slide valve |
| B. | To convert reciprocating motion of the piston into rotary motion of the crank |
| C. | To convert rotary motion of the crankshaft into to and fro motion of the valve rod |
| D. | To provide simple harmonic motion to the D-slide valve |
| Answer» E. | |
| 281. |
The rate of steam produced in Benson boiler is%! |
| A. | 100 tonnes/h |
| B. | 135 tonnes/h |
| C. | 175 tonnes/h |
| D. | 250 tonnes/h |
| Answer» C. 175 tonnes/h | |
| 282. |
One kilowatt-hour energy is equivalent to%! |
| A. | 1000 J |
| B. | 360 kJ |
| C. | 3600 kJ |
| D. | 3600 kW/sec |
| Answer» D. 3600 kW/sec | |
| 283. |
By compounding the expansion of steam in two or more cylinders, the length of stroke%! |
| A. | Does not change |
| B. | Increases |
| C. | Decreases |
| D. | None of these |
| Answer» D. None of these | |
| 284. |
Which of the following gases has the highest calorific value?%! |
| A. | Producer gas |
| B. | Coal gas |
| C. | Water gas |
| D. | Blast furnace gas |
| Answer» C. Water gas | |
| 285. |
The compounding of turbines is done in order to%! |
| A. | Reduce speed of rotor |
| B. | Improve efficiency |
| C. | Reduce exit losses |
| D. | All of these |
| Answer» E. | |
| 286. |
A supercritical boiler is one that operates above the pressure and temperature of following values%! |
| A. | 100 kg/cm² and 540°C |
| B. | 1 kg/cm² and 100°C |
| C. | 218 kg/cm² abs and 373°C |
| D. | 218 kg/cm² abs and 540°C |
| Answer» D. 218 kg/cm¬¨‚⧠abs and 540¬¨‚àûC | |
| 287. |
The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.%! |
| A. | Same |
| B. | Less |
| C. | More |
| D. | None of these |
| Answer» C. More | |
| 288. |
Which is not correct statement about effect of sulphur in fuel?%! |
| A. | It has heating value |
| B. | It helps in electrostatic precipitation of ash in flue gases |
| C. | It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low |
| D. | It erodes furnace walls |
| Answer» E. | |
| 289. |
Expanding steam to a very low pressure (high vacuum) in steam engines is%! |
| A. | Desirable |
| B. | Economical |
| C. | Essential |
| D. | Uneconomical |
| Answer» E. | |
| 290. |
The blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.%! |
| A. | 10 to 15% |
| B. | 15 to 20% |
| C. | 20 to 30% |
| D. | 30 to 40% |
| Answer» B. 15 to 20% | |
| 291. |
A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be%! |
| A. | 79 m/s |
| B. | 188 m/s |
| C. | 450 m/s |
| D. | 900 m/s |
| Answer» D. 900 m/s | |
| 292. |
The reheat factor is the ratio of the%! |
| A. | Cumulative heat drop to the isentropic heat drop |
| B. | Isentropic heat drop to the heat supplied |
| C. | Total useful heat drop to the total isentropic heat drop |
| D. | None of the above |
| Answer» B. Isentropic heat drop to the heat supplied | |
| 293. |
*$_Lancashire boiler is of? |
| A. | Stationary < fire tube type |
| B. | Horizontal type |
| C. | Natural circulation type |
| D. | All of the above |
| Answer» E. | |
| 294. |
*$_Locomotive boiler is of the following type? |
| A. | Multi tubular |
| B. | Horizontal |
| C. | Internally fired |
| D. | All of the above |
| Answer» E. | |
| 295. |
*$_An economiser is installed in a boiler primarily to? |
| A. | Superheat the steam |
| B. | Reduce fuel consumption |
| C. | Increase steam pressure |
| D. | All of these |
| Answer» C. Increase steam pressure | |
| 296. |
*$_The natural draught is produced by? |
| A. | Steam jet |
| B. | Centrifugal fan |
| C. | Chimney |
| D. | Both (A) and (B) |
| Answer» D. Both (A) and (B) | |
| 297. |
*$_The process of maintaining the speed of the turbine constant for various load conditions, is known as? |
| A. | Bleeding |
| B. | Reheating |
| C. | Governing |
| D. | None of these |
| Answer» D. None of these | |
| 298. |
*$_For the same length of stroke and speed of crankshaft, the piston speed for a double acting steam engine is _________ the piston speed of single acting steam engine.? |
| A. | Equal to |
| B. | Twice |
| C. | Three times |
| D. | Four times |
| Answer» C. Three times | |
| 299. |
*$_When the inlet pressure of steam is equal to the exit pressure, then? |
| A. | There is a pressure drop in the nozzle |
| B. | Fluid flows through the nozzle |
| C. | Pressure drops and fluid flows through the nozzle |
| D. | There is no pressure drop and fluid does not flow through the nozzle |
| Answer» E. | |
| 300. |
*$_On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by? |
| A. | Horizontal straight line |
| B. | Vertical straight line |
| C. | Straight inclined line |
| D. | Curved line |
| Answer» B. Vertical straight line | |