MCQOPTIONS
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MCQOPTIONS
This section includes 198 Mcqs, each offering curated multiple-choice questions to sharpen your GATE (Mechanical Engineering) knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
The overshot water wheels are those in which the wheel runs entirely by the __________ of water. |
| A. | weight |
| B. | impulse |
| C. | Can't say |
| D. | None of these |
| Answer» B. impulse | |
| 152. |
The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as |
| A. | normal speed |
| B. | unit speed |
| C. | specific speed |
| D. | none of these |
| Answer» D. none of these | |
| 153. |
For centrifugal pump impeller, the maximum value of the vane exit angle is |
| A. | 10° to 15° |
| B. | 15° to 20° |
| C. | 20° to 25° |
| D. | 25° to 30° |
| Answer» D. 25° to 30° | |
| 154. |
In a reaction turbine, the pressure head of water, while flowing over the vanes, is converted into kinetic head before leaving the wheel. |
| A. | Agree |
| B. | Disagree |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 155. |
Manometric head, in case of a centrifugal pump, is equal to |
| A. | Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe |
| B. | Workdone per kN of water - Losses within the impeller |
| C. | Energy per kN at outlet of impeller - Energy per kN at inlet of impeller |
| D. | all of the above |
| Answer» E. | |
| 156. |
The force exerted by a jet of water (in a direction normal to flow) impinging on a fixed plate inclined at an angle θ with the jet is |
| A. | (waV/2g) × sin θ |
| B. | (waV/g) × sin θ |
| C. | (waV²/2g) × sin 2θ |
| D. | (waV²/g) × sin θ |
| Answer» D. (waV²/g) × sin θ | |
| 157. |
Which of the following pump is preferred for flood control and irrigation applications? |
| A. | Centrifugal pump |
| B. | Axial flow pump |
| C. | Mixed flow pump |
| D. | Reciprocating pump |
| Answer» C. Mixed flow pump | |
| 158. |
The efficiency of a Pelton wheel working under constant head __________ with the increase in power. |
| A. | remains same |
| B. | increases |
| C. | decreases |
| D. | None of these |
| Answer» C. decreases | |
| 159. |
The discharge of a centrifugal pump working under constant head __________ with the speed. |
| A. | increases |
| B. | decreases |
| C. | Can't say |
| D. | None of these |
| Answer» B. decreases | |
| 160. |
The unit discharge through the turbine is |
| A. | Q/√H |
| B. | Q/H |
| C. | Q/H3/2 |
| D. | Q/H² |
| Answer» B. Q/H | |
| 161. |
Delivery head of water of a centrifugal pump is inversely proportional to diameter of its impeller. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 162. |
Which of the following turbine is preferred for 0 to 25 m head of water? |
| A. | Pelton wheel |
| B. | Kaplan turbine |
| C. | Francis turbine |
| D. | none of these |
| Answer» C. Francis turbine | |
| 163. |
The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.) |
| A. | L.A.N |
| B. | 2 L.A.N |
| C. | (L.A.N)/60 |
| D. | (2 L.A.N)/60 |
| Answer» E. | |
| 164. |
The speed ratio of a Francis turbine is defined as the ratio of the theoretical jet velocity to the peripheral speed at inlet. |
| A. | Yes |
| B. | No |
| C. | Can't say |
| D. | None of these |
| Answer» C. Can't say | |
| 165. |
The overall efficiency of a reaction turbine is the ratio of |
| A. | power produced by the turbine to the energy actually supplied by the turbine |
| B. | actual work available at the turbine to the energy imparted to the wheel |
| C. | workdone on the wheel to the energy (or head of water) actually supplied to the turbine |
| D. | none of the above |
| Answer» B. actual work available at the turbine to the energy imparted to the wheel | |
| 166. |
Work done by a turbine __________ upon the weight of water flowing per second. |
| A. | depends |
| B. | does not depend |
| C. | Can't say |
| D. | None of these |
| Answer» B. does not depend | |
| 167. |
Maximum impulse will be developed in hydraulic ram when |
| A. | waste valve closes suddenly |
| B. | supply pipe is long |
| C. | supply pipe is short |
| D. | ram chamber is large |
| Answer» B. supply pipe is long | |
| 168. |
A hydraulic accumulator normally consists of |
| A. | two cylinders, two rams and a storage device |
| B. | a cylinder and a ram |
| C. | two co-axial rams and two cylinders |
| D. | a cylinder, a piston, storage tank and control valve |
| Answer» C. two co-axial rams and two cylinders | |
| 169. |
Pressure intensifier increases the pressure in proportion to |
| A. | ratio of diameters |
| B. | square of ratio of diameters |
| C. | inverse ratio of diameters |
| D. | square of inverse ratio of diameters |
| Answer» C. inverse ratio of diameters | |
| 170. |
According to fan laws, at constant weight of air or gas, the speed, capacity and pressure vary |
| A. | directly as the air or gas density |
| B. | inversely as square root of density |
| C. | inversely as density |
| D. | as square of density |
| Answer» D. as square of density | |
| 171. |
Air vessels in reciprocating pump are used to |
| A. | smoothen flow |
| B. | reduce acceleration to minimum |
| C. | increase pump efficiency |
| D. | save pump from cavitation |
| Answer» C. increase pump efficiency | |
| 172. |
Which place in hydraulic turbine is most susceptible for cavitation |
| A. | inlet of draft rube |
| B. | blade inlet |
| C. | guide blade |
| D. | penstock |
| Answer» B. blade inlet | |
| 173. |
The angle of taper on draft tube is |
| A. | greater than 15° |
| B. | greater than 8° |
| C. | less than 5° |
| D. | less than 8° |
| Answer» E. | |
| 174. |
The discharge through a reaction turbine with increase in unit speed |
| A. | increases |
| B. | decreases |
| C. | remains unaffected |
| D. | first increases and then decreases |
| Answer» C. remains unaffected | |
| 175. |
Reaction turbines are used for |
| A. | low head |
| B. | high head |
| C. | high head and low discharge |
| D. | low head and high discharge. |
| Answer» E. | |
| 176. |
The flow rate in gear pump |
| A. | increases with increase in pressure |
| B. | decreases with increase in pressure |
| C. | more or less remains constant with in-crease in pressure |
| D. | unpredictable |
| Answer» D. unpredictable | |
| 177. |
Francis turbine is best suited for |
| A. | medium head application from 24 to 180 m |
| B. | low head installation up to 30 m |
| C. | high head installation above 180 m |
| D. | all types of heads |
| Answer» B. low head installation up to 30 m | |
| 178. |
Guide angle as per the aerofoil theory of Kaplan turbine blade design is defined as the angle between |
| A. | lift and resultant force |
| B. | drag and resultant force |
| C. | lift and tangential force |
| D. | lift and drag |
| Answer» B. drag and resultant force | |
| 179. |
A turbine pump is basically a centrifugal pump equipped additionally with |
| A. | adjustable blades |
| B. | backward curved blades |
| C. | vaned diffusion casing |
| D. | inlet guide blades |
| Answer» D. inlet guide blades | |
| 180. |
Puck up the wrong statement about centrifugal pump |
| A. | discharge a diameter |
| B. | head a speed |
| C. | head a diameter |
| D. | Power a speed |
| Answer» B. head a speed | |
| 181. |
The specific speed of turbine is defined as the speed of a unit |
| A. | of such a size that it delivers unit dis-charge at unit head |
| B. | of such a size that it delivers unit dis-charge at unit power |
| C. | of such a size that it requires unit power per unit head |
| D. | of such a size that it produces unit horse power with unit head |
| Answer» E. | |
| 182. |
The maximum number of jets generally employed in impulse turbine without jet interference is |
| A. | 4 |
| B. | 6 |
| C. | 8 |
| D. | 12 |
| Answer» C. 8 | |
| 183. |
Runaway speed of a hydraulic turbine is |
| A. | full load speed |
| B. | the speed at which turbine runner will be damaged |
| C. | the speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open |
| D. | the speed corresponding to maximum overload permissible |
| Answer» D. the speed corresponding to maximum overload permissible | |
| 184. |
Any change in load is adjusted by adjusting following parameter on turbine |
| A. | net head |
| B. | absolute velocity |
| C. | blade velocity |
| D. | flow |
| Answer» E. | |
| 185. |
High specific speed of a pump implies it is |
| A. | centrifugal pump |
| B. | mixed flow pump |
| C. | axial flow pump |
| D. | any one of the above |
| Answer» D. any one of the above | |
| 186. |
Medium specific speed of a pump implies it is |
| A. | centrifugal pump |
| B. | mixed flow pump |
| C. | axial flow pump |
| D. | any one of the above |
| Answer» C. axial flow pump | |
| 187. |
In centrifugal pumps, maximum efficiency is obtained when the blades are |
| A. | straight |
| B. | bent forward |
| C. | bent backward |
| D. | radial |
| Answer» D. radial | |
| 188. |
For small discharge at high pressure, following pump is preferred |
| A. | centrifugal |
| B. | axial flow |
| C. | mixed flow |
| D. | reciprocating. |
| Answer» E. | |
| 189. |
In a centrifugal pump, the liquid enters the pump |
| A. | at the top |
| B. | at the bottom |
| C. | at the center |
| D. | from sides |
| Answer» D. from sides | |
| 190. |
The horse power required in above case will be |
| A. | same |
| B. | 0.75 B.H.P. |
| C. | B.H.P./0.75 |
| D. | 1.5 B.H.P. |
| Answer» C. B.H.P./0.75 | |
| 191. |
If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge |
| A. | same quantity of liquid |
| B. | 0.75 Q |
| C. | Q/0.75 |
| D. | 1.5 Q |
| Answer» B. 0.75 Q | |
| 192. |
In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by |
| A. | designing new impeller |
| B. | trimming the impeller size to the required size by machining |
| C. | not possible |
| D. | some other alterations in the impeller |
| Answer» C. not possible | |
| 193. |
One horsepower is equal to |
| A. | 102 watts |
| B. | 75 watts |
| C. | 550 watts |
| D. | 735 watts |
| Answer» E. | |
| 194. |
When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be |
| A. | horizontal |
| B. | nearly horizontal |
| C. | steep |
| D. | first rise and then fall |
| Answer» D. first rise and then fall | |
| 195. |
In a centrifugal pump casing, the flow of water leaving the |
| A. | radial |
| B. | centrifugal |
| C. | rectilinear |
| D. | vortex |
| Answer» E. | |
| 196. |
The efficiency of a centrifugal pump is maximum when its blades are |
| A. | straight |
| B. | bent forward |
| C. | bent backward |
| D. | bent forward first and then backward |
| Answer» D. bent forward first and then backward | |
| 197. |
For starting an axial flow pump, its delivery valve should be |
| A. | closed |
| B. | open |
| C. | depends on starting condition and flow desired |
| D. | could be either open or closed |
| Answer» C. depends on starting condition and flow desired | |
| 198. |
Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of |
| A. | high initial and maintenance cost |
| B. | lower discharge |
| C. | lower speed of operation |
| D. | necessity of air vessel |
| Answer» B. lower discharge | |