McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 151. |
generating power |
| A. | thermal power |
| B. | nuclear power |
| C. | hydroelectric power |
| D. | electric power |
| Answer» C. hydroelectric power | |
| Explanation: hydraulic energy is renewable source of energy in which potential energy of water is converted to mechanical energy which is connected to dynamo to generate electrical energy. | |
| 152. |
Pen stocks are made up of |
| A. | steel |
| B. | cast iron |
| C. | mild steel |
| D. | wrought iron |
| Answer» A. steel | |
| Explanation: penstocks are channels which transport water from reservoir to turbines which are usually made up of cast iron or concrete. | |
| 153. |
turbines, if vanes are fixed to hub of turbine |
| A. | propeller turbine |
| B. | francis turbine |
| C. | kaplan turbine |
| D. | pelton turbine |
| Answer» A. propeller turbine | |
| Explanation: axial flow turbine is a turbine in which water flows axially outwards, if vanes are fixed to hub of turbine it is known as propeller turbine but if vanes are free to move it is known as kaplan turbine. | |
| 154. |
The important type of axial flow reaction turbines are |
| A. | propeller and pelton turbines |
| B. | kaplan and francis turbines |
| C. | propeller and francis turbines |
| D. | propeller and kaplan turbines |
| Answer» D. propeller and kaplan turbines | |
| Explanation: axial flow turbine is a turbine in which water flows axially outwards and turbines fall into this category are propeller and kaplan turbines. | |
| 155. |
Specific speed of reaction turbine is between? |
| A. | 5 and 50 |
| B. | 10 and 100 |
| C. | 100 and 150 |
| D. | 150 and 300 |
| Answer» B. 10 and 100 | |
| Explanation: specific turbines of reaction turbines such as francis and kaplan lie under the range 10-100. | |
| 156. |
Impulse turbine is generally fitted at |
| A. | at the level of tail race |
| B. | above the tail race |
| C. | below the tail race |
| D. | about 2.5mts above tail race to avoid cavitations. |
| Answer» B. above the tail race | |
| Explanation: impulse turbine is fitted above | |
| 157. |
Draft tube is also called |
| A. | straight divergent tube |
| B. | simple elbow tube |
| C. | thermal tube |
| D. | elbow tube with varying cross section |
| Answer» A. straight divergent tube | |
| Explanation: draft tube is one of the most commonly used in the kaplan turbine. it works as an outlet at the kaplan turbine. | |
| 158. |
A draft tube helps in converting kinetic energy into |
| A. | electrical work |
| B. | mechanical work |
| C. | chemical work |
| D. | thermal work |
| Answer» B. mechanical work | |
| Explanation: turbine extracts energy and converts it into useful work. turbine is a vortex related device. it means turbulence. steam turbine converts energy into mechanical work by extracting thermal energy from pressurized steam. | |
| 159. |
Most common application of the draft tube is |
| A. | rotor |
| B. | motor |
| C. | pump |
| D. | filter |
| Answer» C. pump | |
| Explanation: most common application of the draft tube is different types of pumps. it plays an important role in the putlet of the pump and the turbine. | |
| 160. |
Draft tube consists of conical diffuser with angles of |
| A. | 10 deg |
| B. | 20 deg |
| C. | 30 deg |
| D. | 40 deg |
| Answer» A. 10 deg | |
| Explanation: draft tube consists of conical diffuser with angles of 10 degrees with respect to its position, draft tubes are situated in the outlet of the turbine. | |
| 161. |
What is the purpose of a Draft tube? |
| A. | to prevent flow separation |
| B. | to avoid pressure drag |
| C. | to prevent rejection of heat |
| D. | to increase efficiency |
| Answer» A. to prevent flow separation | |
| Explanation: draft tube in a turbine and pumps helps to prevent flow separation in order to increase the turbine efficiency and increase its performance. | |
| 162. |
What is the maximum value of efficiency in a draft tube? |
| A. | 100 |
| B. | 50 |
| C. | 90 |
| D. | 40 |
| Answer» C. 90 | |
| Explanation: the maximum value of efficiency in a draft tube is 90 percent. it cannot exceed more than 90 percent because of the heat losses due to flow of fluid. | |
| 163. |
Turbine that consists of draft tubes is called as |
| A. | impulse turbine |
| B. | curtis turbine |
| C. | rateau turbine |
| D. | reaction turbine |
| Answer» D. reaction turbine | |
| Explanation: a turbine that consists of draft tubes is called as a reaction turbine. reaction turbines make maximum use of the draft tubes for improving its performance characteristics. | |
| 164. |
Which of the following is a 50 percent reaction turbine? |
| A. | parsons turbine |
| B. | curtis turbine |
| C. | rateau turbine |
| D. | pelton wheel |
| Answer» A. parsons turbine | |
| Explanation: a turbine that consists of moving nozzles which are alternating with the fixed nozzles is called as a reaction turbine. | |
| 165. |
The simple elbow draft tube helps to cut down the cost of excavation. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the simple elbow draft tube helps to cut down the cost of excavation. the simple elbow draft tube is placed close to the | |
| 166. |
The exit diameter for a simple elbow draft tube should be |
| A. | large |
| B. | small |
| C. | very small |
| D. | same |
| Answer» A. large | |
| Explanation: the exit diameter for a simple elbow draft tube should be large as possible. it helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. the simple elbow draft tube is placed close to the tail race. | |
| 167. |
Properties that do not affect a draft tube is |
| A. | pressure |
| B. | temperature |
| C. | pressure velocity |
| D. | velocity |
| Answer» B. temperature | |
| Explanation: temperature does not affect the performance of the draft tube. with increase and decrease of temperature of fluid in a draft tube, the draft tube remains the same. | |
| 168. |
The other name for elbow with varying cross section tube is called |
| A. | pressure tube |
| B. | bent draft tube |
| C. | velocity tube |
| D. | sink tube |
| Answer» B. bent draft tube | |
| Explanation: the other name for elbow with varying cross section tube is called bent draft tube. it is so called because only the bent part is of varying cross section. thus, the answer is bent draft tube. | |
| 169. |
type draft tube? |
| A. | 10 |
| B. | 30 |
| C. | 60 |
| D. | 90 |
| Answer» C. 60 | |
| Explanation: the efficiency of the simple elbow type draft tube is 60 percent. the exit diameter for a simple elbow draft tube should be large as possible. it helps to cut down the cutdown the cost and recover the kinetic energy at the outlet of runner. the simple elbow draft tube is placed close to the tail race. | |
| 170. |
The horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the horizontal portion of the draft tube is usually bent to prevent entry of air from the exit end. this might lead to a mixing up of gases. in order to avoid this, it is important to avoid air entry from exit. | |
| 171. |
In nozzle governing, the flow rate of steam is regulated by |
| A. | nozzles |
| B. | pumping |
| C. | drafting |
| D. | intercooling |
| Answer» A. nozzles | |
| Explanation: the process of controlling the flow rate of a substance is called as | |
| 172. |
The flow rate of steam is controlled by regulating the |
| A. | steam |
| B. | pressure |
| C. | temperature |
| D. | speed |
| Answer» B. pressure | |
| Explanation: the process of controlling the flow rate is called as governing. it is done to maintain its speed at a constant rate during rotation of the turbine rotor. the flow rate of steam is controlled by regulating the pressure. | |
| 173. |
What is primary objective of steam turbine governing? |
| A. | maintain constant speed |
| B. | maintain constant pressure |
| C. | maintain constant temperature |
| D. | maintain constant expansion |
| Answer» A. maintain constant speed | |
| Explanation: the primary objective of steam turbine governing is to maintain a constant speed at varying loads. that means, irrespective of the load that is developed in the turbine, the speed remains a constant. | |
| 174. |
governing? |
| A. | controls speed |
| B. | controls flow rate |
| C. | controls volume |
| D. | controls discharge |
| Answer» B. controls flow rate | |
| Explanation: the main purpose of the steam turbine governing is to control the flow rate of steam in the turbine. it also helps in regulating the load that is developed. | |
| 175. |
Which among the following control the flow rate? |
| A. | valve |
| B. | pump |
| C. | head |
| D. | tank pipe |
| Answer» A. valve | |
| Explanation: flow rate of the tank is controlled by the valve. the actuation of individual valve closes. this corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve. | |
| 176. |
The advantage of nozzle governing is that no regulating pressure is applied. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the advantage of nozzle governing is that no regulating pressure is applied. the actuation of individual valve closes the corresponding set of nozzle. thus, controlling the flow rate. | |
| 177. |
During the steam turbine governing, what remains a constant? |
| A. | speed of rotation |
| B. | flow rate |
| C. | pump head |
| D. | volume of fluid |
| Answer» A. speed of rotation | |
| Explanation: during the steam turbine governing the speed of rotation remains a constant. the main purpose of the steam turbine governing is to control the flow rate of steam in the turbine. it also helps in regulating the load that is developed. | |
| 178. |
When do we apply by pass governing? |
| A. | when turbine is overloaded |
| B. | when unit speed decreases |
| C. | when unit power increases |
| D. | when unit pressure decreases |
| Answer» A. when turbine is overloaded | |
| Explanation: the main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations. this happens occasionally in the working of the turbine. during this, a bypass valve is used. | |
| 179. |
When bypass valve is opened to |
| A. | increase pressure |
| B. | increase unit speed |
| C. | increase unit power |
| D. | increase the amount of fresh steam |
| Answer» D. increase the amount of fresh steam | |
| Explanation: when a by pass valve is opened, a fresh steam is introduced into the turbine, thereby increasing the amount of fresh steam. the main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations. | |
| 180. |
What is the unit of steam rate? |
| A. | kg |
| B. | kg/m |
| C. | kg/kwh |
| D. | n/m |
| Answer» C. kg/kwh | |
| Explanation: the unit of stream is equal to kg/kwh. in the process of throttle governing, it is denoted by the symbol ‘a’. the variation of the steam consumption rate with the turbine load during governing is linear. | |
| 181. |
turbine |
| A. | decreases |
| B. | increases |
| C. | remains same |
| D. | independent |
| Answer» A. decreases | |
| Explanation: when there is an increase in the load, the energy in the turbine is drained off. | |
| 182. |
Combination governing involves usage of two or more governing. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: yes, combination governing involves usage of two or more governing. most usage is the by pass and the nozzle governing as they tend to match the load on the turbine. thus, increasing its efficiency. | |
| 183. |
increases beyond 110 percent, we use |
| A. | throttle governing |
| B. | steam governing |
| C. | nozzle governing |
| D. | emergency governing |
| Answer» D. emergency governing | |
| Explanation: when the mechanical speed of the shaft increases beyond 110 percent, we use emergency governing. these governors come into action only when there are emergencies in the turbine. | |
| 184. |
Which one of the following is the unit of mass density? |
| A. | kg = m3 |
| B. | kg = m2 |
| C. | kg = m |
| D. | kg = ms |
| Answer» A. kg = m3 | |
| 185. |
Which one of the following is the dimension of mass density? |
| A. | [m1 l-3 t0]. |
| B. | [m1 l3 t0]. |
| C. | [m0 l-3 t0]. |
| D. | [m0 l3 t0]. |
| Answer» A. [m1 l-3 t0]. | |
| 186. |
] = [ML-3]. |
| A. | [m1 l-3 t0]. |
| B. | [m1 l0 t0]. |
| C. | [m0 l-3 t0]. |
| D. | [m0 l0 t0]. |
| Answer» D. [m0 l0 t0]. | |
| 187. |
]/[M] = [M-1L3]. |
| A. | [ml-3 t -2]. |
| B. | [ml3 t-2]. |
| C. | [ml-2 t-2]. |
| D. | [ml2 t-2]. |
| Answer» C. [ml-2 t-2]. | |
| 188. |
and v2? |
| A. | v1 > v2 |
| B. | v1 < v2 |
| C. | v1 = v2 |
| D. | cannot be determined due to insufficient information. |
| Answer» B. v1 < v2 | |
| 189. |
A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific weight of the liquid will be |
| A. | 6:5 kn = m3 |
| B. | 6:6 kn = m3 |
| C. | 6:7 kn = m3 |
| D. | 6:8 kn = m3 |
| Answer» A. 6:5 kn = m3 | |
| 190. |
A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific gravity of the liquid will be |
| A. | 0.65 |
| B. | 0.66 |
| C. | 0.67 |
| D. | 0.68 |
| Answer» B. 0.66 | |
| 191. |
A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific volume of the liquid will be |
| A. | 1 l =kg |
| B. | 1:5 l =kg |
| C. | 2 l =kg |
| D. | 2:5 l =kg |
| Answer» B. 1:5 l =kg | |
| 192. |
The physical principle behind the continuity equation is |
| A. | mass conservation |
| B. | zeroth law of thermodynamics |
| C. | first law of thermodynamics |
| D. | energy conservation |
| Answer» A. mass conservation | |
| 193. |
To convert the non-conservative integral equation of mass conservation into the conservative integral form, which of these theorems is used? |
| A. | stokes theorem |
| B. | kelvin-stokes theorem |
| C. | gauss-siedel theorem |
| D. | gauss divergence theorem |
| Answer» D. gauss divergence theorem | |
| 194. |
The vertical intercept between EGL and HGL is equal to |
| A. | pressure head |
| B. | potential head |
| C. | kinetic head |
| D. | piezometric head |
| Answer» C. kinetic head | |
| 195. |
For a diffuser, the vertical intercept between EGL and HGL |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | may increase or decrease |
| Answer» B. decreases | |
| 196. |
For a fully-developed pipe flow, how does the pressure vary with the length of the pipe? |
| A. | linearly |
| B. | parabolic |
| C. | exponential |
| D. | constant |
| Answer» A. linearly | |
| 197. |
The flow separation occurs when the fluid travels away from the |
| A. | surface |
| B. | fluid body |
| C. | adverse pressure gradient |
| D. | inter-molecular spaces |
| Answer» C. adverse pressure gradient | |
| 198. |
Eddy viscosity is a turbulent transfer of |
| A. | fluid |
| B. | heat |
| C. | momentum |
| D. | pressure |
| Answer» C. momentum | |
| 199. |
With the boundary layer separation, displacement thickness |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | independent |
| Answer» A. increases | |
| 200. |
What is the instrument used for the automatic control scheme during the fluid flow? |
| A. | rotameters |
| B. | pulley plates |
| C. | rotary piston |
| D. | pilot static tube |
| Answer» D. pilot static tube | |
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