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MCQOPTIONS
This section includes 219 Mcqs, each offering curated multiple-choice questions to sharpen your Automobile Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
A simple turbo-jet engine is basically a gas turbine engine equipped with a propulsive nozzle and diffuser. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» B. Disagree | |
| 152. |
Standard air is the air at __________ and relative humidity of 36 percent. |
| A. | 0.1 bar and 20° C |
| B. | 1 bar and 20° C |
| C. | 0.1 bar and 40° C |
| D. | 1 bar and 40° C |
| Answer» C. 0.1 bar and 40° C | |
| 153. |
Separators are generally used in air compressor installations |
| A. | before the intercooler |
| B. | after the intercooler |
| C. | between the aftercooler and receiver |
| D. | before first stage suction |
| Answer» D. before first stage suction | |
| 154. |
The volumetric efficiency of the compressor is defined as the ratio of volume of free air delivery per stroke to the swept volume of the piston. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» B. No | |
| 155. |
In the aircraft propellers |
| A. | the propulsive matter is ejected from within the propelled body |
| B. | the propulsive matter is caused to flow around the propelled body |
| C. | its functioning does not depend upon the presence of air |
| D. | none of the above |
| Answer» B. the propulsive matter is caused to flow around the propelled body | |
| 156. |
The efficiency of the vane blower is (where W1 = Workdone due to compression, and W2 = Workdone due to back flow) |
| A. | W₁/(W₁ + W₂) |
| B. | W₂/(W₁ + W₂) |
| C. | (W₁ + W₂)/W₁ |
| D. | (W₁ + W₂)/W₂ |
| Answer» C. (W₁ + W₂)/W₁ | |
| 157. |
For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages. |
| A. | True |
| B. | False |
| C. | Can't say |
| D. | None of these |
| Answer» B. False | |
| 158. |
A closed cycle gas turbine works on |
| A. | Carnot cycle |
| B. | Rankine cycle |
| C. | Ericsson cycle |
| D. | Joule cycle |
| Answer» E. | |
| 159. |
The volume of air delivered by the compressor is called |
| A. | free air delivery |
| B. | compressor capacity |
| C. | swept volume |
| D. | none of these |
| Answer» C. swept volume | |
| 160. |
The efficiency of a jet engine is higher at |
| A. | low speeds |
| B. | high speeds |
| C. | low altitudes |
| D. | high altitudes |
| Answer» E. | |
| 161. |
The reason for volumetric efficiency of reciprocating compressor being less than 100 percent is |
| A. | pressure drop across the valves |
| B. | superheating in compressor |
| C. | clearance volume and leakages |
| D. | all of these |
| Answer» E. | |
| 162. |
The speed of rotary air compressor is __________ as compared to reciprocating air compressor. |
| A. | high |
| B. | low |
| C. | Can't say |
| D. | None of these |
| Answer» B. low | |
| 163. |
Slip factor in a centrifugal compressor indicates the amount of air leaked from the storage vessel. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 164. |
In a centrifugal compressor, the air enters the impeller axially and leaves the vane radially. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 165. |
The workdone on a compressor will be minimum if air is taken from |
| A. | the atmosphere |
| B. | a source at 0° C |
| C. | a source of low temperature air |
| D. | a source of high temperature air |
| Answer» D. a source of high temperature air | |
| 166. |
The minimum work required for a three stage reciprocating air compressor is __________ the work required for each stage. |
| A. | equal to |
| B. | double |
| C. | three times |
| D. | six times |
| Answer» D. six times | |
| 167. |
The perfect intercooling, in multistage compression, means that the temperature of air at inlet to subsequent stages is equal to the initial temperature. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» B. Disagree | |
| 168. |
A compressor mostly used for supercharging of I.C. engines is |
| A. | radial flow compressor |
| B. | axial flow compressor |
| C. | roots blower |
| D. | reciprocating compressor |
| Answer» B. axial flow compressor | |
| 169. |
A rocket engine uses __________ for the combustion of its fuel. |
| A. | surrounding air |
| B. | compressed atmospheric air |
| C. | its own oxygen |
| D. | none of these |
| Answer» D. none of these | |
| 170. |
The thrust of a jet propulsion power unit can be increased by |
| A. | injecting water into the compressor |
| B. | burning fuel after gas turbine |
| C. | injecting ammonia into the combustion chamber |
| D. | all of the above |
| Answer» E. | |
| 171. |
A centrifugal compressor is an axial flow compressor. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 172. |
The ratio of the net work obtained from the gas turbine plant to the turbine work is known as |
| A. | compression ratio |
| B. | work ratio |
| C. | pressure ratio |
| D. | none of these |
| Answer» C. pressure ratio | |
| 173. |
The compressor capacity is defined as the |
| A. | actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions |
| B. | volume of air delivered by the compressor |
| C. | volume of air sucked by the compressor during its suction stroke |
| D. | none of the above |
| Answer» C. volume of air sucked by the compressor during its suction stroke | |
| 174. |
A 3 m³/min compressor means that it |
| A. | compresses 3 m³/min of standard air |
| B. | compresses 3 m³/ min of free air |
| C. | delivers 3 m³/ min of compressed air |
| D. | delivers 3 m³/ min of compressed air at delivery pressure |
| Answer» C. delivers 3 m³/ min of compressed air | |
| 175. |
In a two stage reciprocating compressor with intercooler, the amount of work saved with incomplete intercooling is __________ that in case of complete intercooling. |
| A. | less than |
| B. | more than |
| C. | Can't say |
| D. | None of these |
| Answer» B. more than | |
| 176. |
In a reciprocating air compressor, the compression work per kg of air |
| A. | increases as clearance volume increases |
| B. | decreases as clearance volume increases |
| C. | is independent of clearance volume |
| D. | increases as clearance volume decreases |
| Answer» D. increases as clearance volume decreases | |
| 177. |
The temperature of air at the beginning of the compression stroke is __________ the atmospheric temperature. |
| A. | equal to |
| B. | less than |
| C. | more than |
| D. | None of these |
| Answer» D. None of these | |
| 178. |
For perfect intercooling in a three stage compressor, |
| A. | p₂/p₁ = p₃/p₂ = p₄/p₃ |
| B. | p₃/p₁ = p₄/p₂ |
| C. | p₁ p₂ = p₃ p₄ |
| D. | p₁ p₃ = p₂ p₄ |
| Answer» B. p₃/p₁ = p₄/p₂ | |
| 179. |
A gas turbine used in air-craft should have low weight and small frontal area. |
| A. | Correct |
| B. | Incorrect |
| C. | Can't say |
| D. | None of these |
| Answer» B. Incorrect | |
| 180. |
The compressed air may be used |
| A. | in gas turbine plants |
| B. | for operating pneumatic drills |
| C. | in starting and supercharging of I.C. engines |
| D. | all of the above |
| Answer» E. | |
| 181. |
The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the |
| A. | rotor to static enthalpy rise in the stator |
| B. | stator to static enthalpy rise in the rotor |
| C. | rotor to static enthalpy rise in the stage |
| D. | stator to static enthalpy rise in the stage |
| Answer» D. stator to static enthalpy rise in the stage | |
| 182. |
An axial compressor gives optimum performance at high speeds and large volume flows. |
| A. | Agree |
| B. | Disagree |
| C. | - |
| D. | - |
| Answer» B. Disagree | |
| 183. |
The type of rotary compressor used in aeroplanes, is of |
| A. | centrifugal type |
| B. | axial flow type |
| C. | radial flow type |
| D. | none of these |
| Answer» C. radial flow type | |
| 184. |
The increase in pressure in a roots blower is entirely due to back flow of air. |
| A. | Agree |
| B. | Disagree |
| C. | - |
| D. | - |
| Answer» B. Disagree | |
| 185. |
The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor, is called |
| A. | compressor efficiency |
| B. | volumetric efficiency |
| C. | isothermal efficiency |
| D. | mechanical efficiency |
| Answer» E. | |
| 186. |
If p 1 , is the pressure of air entering the L.P. cylinder and p 2 is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D 1 = Dia. of L.P. cylinder, and D 2 = Dia. of H.P. cylinder) |
| A. | D 1 / D 2 = p 1 p 2 |
| B. | D 1 / D 2 = p 1 / p 2 |
| C. | D 1 / D 2 = p 2 / p 1 |
| D. | none of these |
| Answer» D. none of these | |
| 187. |
The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as |
| A. | compressor efficiency |
| B. | volumetric efficiency |
| C. | isothermal efficiency |
| D. | mechanical efficiency |
| Answer» C. isothermal efficiency | |
| 188. |
An aftercooler is used to |
| A. | remove impurities from air |
| B. | reduce volume of air |
| C. | cause moisture and oil vapour to drop out |
| D. | cool the air |
| Answer» D. cool the air | |
| 189. |
The maximum combustion pressure in gas turbine is __________ as compared to I.C. engine. |
| A. | more |
| B. | less |
| C. | - |
| D. | - |
| Answer» C. - | |
| 190. |
Intercooling in compressors results in saving of power in compressing given volume of air to a given pressure. |
| A. | Correct |
| B. | Incorrect |
| C. | - |
| D. | - |
| Answer» B. Incorrect | |
| 191. |
The compression ratio in a gas turbine is |
| A. | 4 |
| B. | 1 |
| C. | 9 |
| D. | 12 |
| Answer» C. 9 | |
| 192. |
The actual volume of air delivered by a compressor, When reduced to the normal temperature and pressure conditions is called compressor capacity. |
| A. | Yes |
| B. | No |
| C. | - |
| D. | - |
| Answer» C. - | |
| 193. |
When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is __________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling. |
| A. | equal to |
| B. | less than |
| C. | more than |
| D. | - |
| Answer» B. less than | |
| 194. |
Intercooling in gas turbines |
| A. | decreases net output but increases thermal efficiency |
| B. | increases net output but decreases thermal efficiency |
| C. | decreases net output and thermal efficiency both |
| D. | increases net output and thermal efficiency both |
| Answer» C. decreases net output and thermal efficiency both | |
| 195. |
Gas turbine as compared to steam turbine |
| A. | requires less space for installation |
| B. | has compressor and combustion chamber |
| C. | has less efficiency |
| D. | all of these |
| Answer» E. | |
| 196. |
A closed cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine. |
| A. | same |
| B. | lower |
| C. | higher |
| D. | - |
| Answer» D. - | |
| 197. |
A large clearance Volume in a reciprocating compressor results in |
| A. | reduced volume flow rate |
| B. | increased volume flow rate |
| C. | lower suction pressure |
| D. | lower delivery pressure |
| Answer» B. increased volume flow rate | |
| 198. |
In a centrifugal compressor, an increase in speed at a given pressure ratio causes |
| A. | increase in flow |
| B. | decrease in flow |
| C. | increase in efficiency |
| D. | increase in flow and decrease in efficiency |
| Answer» E. | |
| 199. |
Workdone by a two-stage reciprocating air compressor per cycle is equal to the workdone in LP. cylinder and H.P. cylinder. |
| A. | True |
| B. | False |
| C. | - |
| D. | - |
| Answer» B. False | |
| 200. |
In axial flow compressor, exit flow angle deviation from the blade angle is a function of |
| A. | blade camber |
| B. | blade camber and incidence angle |
| C. | space-chord ratio |
| D. | blade camber and space-chord ratio |
| Answer» C. space-chord ratio | |