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MCQOPTIONS
This section includes 460 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Engines knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
The temperatures and pressures for boiler are given below. Which of these boilers can be classified as super-critical pressure boiler? |
| A. | 250 psi, 150?C |
| B. | 100 kg/cm2, 450?C |
| C. | 10 kg/cm2, 150?C |
| D. | 150 kg/cm2, 500?C |
| E. | 218 kg/cm2, 540?C |
| Answer» F. | |
| 152. |
High steam and low water safety valve is not used on which of the following boiler? |
| A. | Locomotive boiler |
| B. | Cornish boiler |
| C. | Cochran boiler |
| D. | Lancashire boiler |
| E. | All of the above |
| Answer» B. Cornish boiler | |
| 153. |
Which of the following exists as highest pressure in a diesel engine |
| A. | Exhaust gases in silencer |
| B. | Lubricating oil |
| C. | Fuel at the time of injection |
| D. | Air at the end of compression stroke |
| E. | Air during suction |
| Answer» D. Air at the end of compression stroke | |
| 154. |
In an analysis report of a sample of coal the percentage of one of the constituents is specified as 3.5%. This constituent could be |
| A. | Carbon |
| B. | Ash |
| C. | Moisture |
| D. | Sulphur |
| E. | Any of the above |
| Answer» E. Any of the above | |
| 155. |
Thermodynamic equilibrium is completely defined by the specifications of the |
| A. | Internal energy |
| B. | Enthalpy |
| C. | Generalized displacements |
| D. | All above together |
| E. | None of the above |
| Answer» E. None of the above | |
| 156. |
In a velocity compounded impulse turbine, while steam flows through the second row of moving blades |
| A. | The velocity increases |
| B. | The velocity reduces |
| C. | Both velocity as well as pressure increase |
| D. | The velocity remains constant |
| E. | The pressure remains constant |
| Answer» C. Both velocity as well as pressure increase | |
| 157. |
Inlet valve of a IC engine remains open for |
| A. | 180? |
| B. | 250? |
| C. | 300? |
| D. | 150? |
| E. | 280? |
| Answer» C. 300? | |
| 158. |
In a reaction turbine while steam flows through the fixed blades |
| A. | Velocity increases |
| B. | Velocity decreases |
| C. | Velocity increases while pressure drops |
| D. | Pressure increases |
| E. | Neither admission pressure nor cut off is varied |
| Answer» D. Pressure increases | |
| 159. |
The amount of exhaust gases in clearance space left after exhaust stroke, varies with |
| A. | Clearance volume |
| B. | Carbon dioxide |
| C. | air-fuel ratio of charger |
| D. | Speed and load of the engine |
| E. | Bore and length of cylinder |
| Answer» E. Bore and length of cylinder | |
| 160. |
Compression ratio for spark ignition engines varies in the range |
| A. | 6 to 12 |
| B. | 20 to 25 |
| C. | 4 to 6 |
| D. | 25 to 30 |
| E. | 12 to 20 |
| Answer» B. 20 to 25 | |
| 161. |
In an engine radiator, heat is transferred by |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Conduction and convection |
| E. | None of the above |
| Answer» E. None of the above | |
| 162. |
In a spark ignition engine supercharging |
| A. | Decreases knocking tendency |
| B. | There is no effect on knocking |
| C. | Increases knocking tendency |
| D. | Knocking is affected by other factors |
| E. | 1000 hours |
| Answer» D. Knocking is affected by other factors | |
| 163. |
Which of the following offers best resistance to knocking in S.I. engines? |
| A. | Aromatics |
| B. | Paraffins |
| C. | Carbon dioxide |
| D. | Naphthenes |
| E. | Olefins |
| Answer» B. Paraffins | |
| 164. |
Enthalpy of a substance is defined as |
| A. | The sum of internal energy and the work done in forcing unit mass of substance into an enclosure at the constant pressure at which the substance exists |
| B. | Sum of sensible heat + latent heat of substance |
| C. | Total heat content of substance above zero degree centigrade |
| D. | Sensible heat of water + work done in forcing unit mass of substance into an enclosure at constant pressure at which the substance exists |
| E. | None of the above |
| Answer» D. Sensible heat of water + work done in forcing unit mass of substance into an enclosure at constant pressure at which the substance exists | |
| 165. |
Which turbine has identical fixed and moving blades |
| A. | Carbon dioxide |
| B. | De Laval turbine |
| C. | Parson's reaction turbine |
| D. | Rateau's turbine |
| E. | Hero's turbine |
| Answer» D. Rateau's turbine | |
| 166. |
For spark ignition engines fuel in order of decreasing knock tendency are |
| A. | Paraffins, aromatics, naphthenes |
| B. | Paraffins, naphthenes, armatics |
| C. | Aromatics, paraffins, naphthenes |
| D. | Naphthenes, aromatics, paraffins |
| E. | Naphthenes, paraffins |
| Answer» C. Aromatics, paraffins, naphthenes | |
| 167. |
Higher proportion of residual gases in the cylinder would mean |
| A. | Higher volumetric efficiency |
| B. | Lower volumetric efficiency |
| C. | No change in volumetric efficiency |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» C. No change in volumetric efficiency | |
| 168. |
In spark ignition engines the knocking tendency decreases |
| A. | As compression ratio is reduced |
| B. | By controlling air/fuel mixture |
| C. | By controlling ignition timing |
| D. | By controlling exhaust temperatures |
| E. | None of the above |
| Answer» B. By controlling air/fuel mixture | |
| 169. |
An exciter is a |
| A. | D.C. motor |
| B. | D.C.generator |
| C. | A.C.generator |
| D. | Synchronous motor |
| E. | None of the above |
| Answer» C. A.C.generator | |
| 170. |
The steam pressure in a pass out turbine may be expected to be in the range |
| A. | 10 kg/cm2 to 20 kg/cm2 |
| B. | 100 kg/cm2 to 150 kg/cm2 |
| C. | 150 kg/cm2 to 300 kg/cm2 |
| D. | 75 kg/cm2 to 100 kg/cm2 |
| E. | 40 kg/cm2 to 75 kg/cm2 |
| Answer» B. 100 kg/cm2 to 150 kg/cm2 | |
| 171. |
Iso-octane has octane number of |
| A. | 100 |
| B. | 0 |
| C. | 50 |
| D. | 80 to 85 |
| E. | More than 100 |
| Answer» B. 0 | |
| 172. |
Movement of air inside engine cylinder does not help in |
| A. | Distribution of fuel |
| B. | Mixing of fuel with air |
| C. | Reduction of after burning |
| D. | Reducing noise |
| E. | None of the above |
| Answer» E. None of the above | |
| 173. |
An engine operates at 1440 rpm under load whereas no load speed is 1500 rpm. The percentage speed drop of governor will be |
| A. | 2% |
| B. | 3% |
| C. | 4% |
| D. | 10% |
| E. | 6% |
| Answer» D. 10% | |
| 174. |
Freezing point of petrol is around |
| A. | ?4?C |
| B. | ?30?C |
| C. | 10?C |
| D. | ?13?C |
| E. | 0?C |
| Answer» C. 10?C | |
| 175. |
In a Bomb calorimeter the fuel to be tested is burnt |
| A. | At constant volume |
| B. | At constant pressure |
| C. | There is no consideration of volume or pressure |
| D. | In open atmosphere |
| E. | At constant temperature |
| Answer» B. At constant pressure | |
| 176. |
The performance of air compressor at high altitudes as compared to that at sea level will be |
| A. | Will depend upon temperature of air |
| B. | Will depend on type of compressor |
| C. | Better |
| D. | Same |
| E. | Inferior |
| Answer» F. | |
| 177. |
In case of supersonic flow through the nozzle, when the cross-section increases in the direction of flow |
| A. | The velocity will decrease in the direction of flow |
| B. | The pressure will increase in the direction of flow |
| C. | The velocity will increase while the pressure will decrease in the direction of flow |
| D. | The velocity will decrease while the pressure will increase in the direction of flow |
| E. | None of the above |
| Answer» D. The velocity will decrease while the pressure will increase in the direction of flow | |
| 178. |
An economiser is installed in a boiler plant primarily to |
| A. | Increase steam pressure |
| B. | Increase rate of steam evaporation |
| C. | Superheat the steam |
| D. | Purify boiler feed water |
| E. | Reduce fuel consumption |
| Answer» F. | |
| 179. |
Stuffing box is provided in |
| A. | Condensing steam engines |
| B. | Non-condensing steam engines |
| C. | High speed steam engines |
| D. | Single acting steam engines |
| E. | Double acting steam engines |
| Answer» F. | |
| 180. |
A regenerator in a gas turbine |
| A. | Reduces heat loss in exhaust |
| B. | permits use of higher compression ratio |
| C. | Improves thermal efficiency |
| D. | Permits use of fuels of inferior quality |
| E. | None of the above |
| Answer» D. Permits use of fuels of inferior quality | |
| 181. |
The most effective air cleaner for diesel engines is |
| A. | Whirl type |
| B. | Oil bath type |
| C. | Dry type |
| D. | Rope type |
| E. | Wet type |
| Answer» C. Dry type | |
| 182. |
Free piston engines find application in |
| A. | Compressed air supply |
| B. | Mining installations |
| C. | Gas turbines |
| D. | Supercharging of diesel engines |
| E. | None of the above |
| Answer» D. Supercharging of diesel engines | |
| 183. |
The equilibrium conditions between supersaurated vapour and a cooled liquid surface are expressed in |
| A. | Dalton's equation |
| B. | Napier's equation |
| C. | Kelvin Helmhotz equation |
| D. | Clapcyron's equation |
| E. | Calender's equation |
| Answer» D. Clapcyron's equation | |
| 184. |
In pumped storage systems, water is pumped |
| A. | Upstream during peak load periods |
| B. | Upstream during off peak periods |
| C. | Upstream during off season |
| D. | None of the above |
| E. | None of the above |
| Answer» C. Upstream during off season | |
| 185. |
To avoid moisture trubles, the branch connection from compressed air line are taken from |
| A. | Top side |
| B. | Bottom side |
| C. | Left side |
| D. | Any side |
| E. | Right side |
| Answer» B. Bottom side | |
| 186. |
Most of the heat generated in I.C. engines is transferred to surrounding medium by |
| A. | Conduction only |
| B. | Convection only |
| C. | Conduction and convection |
| D. | Radiation only |
| E. | None of the above |
| Answer» D. Radiation only | |
| 187. |
One horse power-hr is equal to |
| A. | 1 kWh |
| B. | 632 kcal |
| C. | 100,000 kJ |
| D. | 107 Joules |
| E. | None of the above |
| Answer» C. 100,000 kJ | |
| 188. |
In a condensing steam engine |
| A. | Exhaust steam is condensed in condenser |
| B. | Exhaust steam is not recirculated |
| C. | Steam condenses as soon as it leaves the cylinder |
| D. | Condensed steam is supplied |
| E. | Steam condenses inside cylinder |
| Answer» B. Exhaust steam is not recirculated | |
| 189. |
In multistages turbines by introducting reheating |
| A. | Thermal efficiency improves |
| B. | The output of turbine increases |
| C. | Work done by compressor reduces |
| D. | The ratio compressor compressor work/turbine output decreases |
| E. | None of the above |
| Answer» B. The output of turbine increases | |
| 190. |
The air standard efficiency of a Diesel engine depends on |
| A. | Speed |
| B. | Torque |
| C. | Thermodynamic properties of working fluid |
| D. | Cetane value of fuel used |
| E. | Compression ratio |
| Answer» F. | |
| 191. |
The Apparatus used for the determination of calorific value of solid fuel is |
| A. | Bunsen's apparatus |
| B. | Photo calorimeter |
| C. | Bomb calorimeter |
| D. | Releigh apparatus |
| E. | Osrat's apparatus |
| Answer» D. Releigh apparatus | |
| 192. |
In a diesel engine the injection pressure is of the order of |
| A. | 1500 kg/cm2 |
| B. | 100 kg/cm2 |
| C. | 1000 kg/cm2 |
| D. | 40 kg/cm2 |
| E. | 500 kg/cm2 |
| Answer» C. 1000 kg/cm2 | |
| 193. |
Pour point is the temperature at which oil |
| A. | Starts cracking |
| B. | Will start flowing |
| C. | Barely flows |
| D. | Will ignite |
| E. | Will give off vapours enough for ignition |
| Answer» D. Will ignite | |
| 194. |
The size of a steam engine is 200 x 250 - 300 r.p.m. In this 200 indicates |
| A. | Shaft diameter |
| B. | Steam pressure in 1bs/sq. in. |
| C. | Piston stroke |
| D. | Horse power |
| E. | Cylinder bore |
| Answer» F. | |
| 195. |
Which of the following boiler uses exhaust of the engine to produce draught? |
| A. | Lamont boiler |
| B. | Cornish boiler |
| C. | Babcock and wilcox boiler |
| D. | Lancashire boiler |
| E. | Locomotive boiler |
| Answer» F. | |
| 196. |
Specific heat is |
| A. | The amount of heat required to raise the temperature of a unit quantity of substance through 1?C |
| B. | The amount of heat requred to change the state or condition under which a substance exists without changing its temperature |
| C. | The ratio of quantity of heat required to raise the temperature of a given weight of any substance through 1?C to the quantity of heat required to raise the temperature of same weight of water through 1?C |
| D. | The heat sensed by a mercury thermometer |
| E. | None of the above |
| Answer» D. The heat sensed by a mercury thermometer | |
| 197. |
In centrifugal pumps suction head is |
| A. | Vertical distance from supply level to pump centre line pump being level |
| B. | (A) Above less suction friction heat |
| C. | (A) Above less velocity heat |
| D. | Any of the above |
| E. | None of the above |
| Answer» D. Any of the above | |
| 198. |
In Eicher tractor the engine is |
| A. | Air cooled |
| B. | Horizontal |
| C. | Multi-cylinder type |
| D. | Low compression ratio petrol engine |
| E. | Constant speed engine |
| Answer» B. Horizontal | |
| 199. |
In order to reduce wear and eliminate scuffing, piston ring in internal combustion engines are |
| A. | Made of soft material |
| B. | Provided with grooves |
| C. | Lubricated thoroughly |
| D. | Made of square section |
| E. | Plated with chromium, cadmium or phosphate |
| Answer» F. | |
| 200. |
The higher the temperature required to ignite diesel fuel, |
| A. | Lower the octane number |
| B. | Carbon dioxide |
| C. | Lower the cetane number |
| D. | Higher the cetane number |
| E. | the higher the octane number |
| Answer» D. Higher the cetane number | |