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MCQOPTIONS
This section includes 2670 Mcqs, each offering curated multiple-choice questions to sharpen your Railways knowledge and support exam preparation. Choose a topic below to get started.
| 1251. |
In a vapour compression refrigeration system, throttle valve is used in place of an expander because: |
| A. | It considerably reduces the system weight. |
| B. | It improves the COP, as the condenser is small. |
| C. | The positive work in isentropic expansion of liquid is very small. |
| D. | It leads to significant cost reduction. |
| Answer» D. It leads to significant cost reduction. | |
| 1252. |
The minimum temperature to which water can be cooled in a cooling tower is: |
| A. | The dew point temperature of air |
| B. | The wet-bulb temperature of air |
| C. | The dry bulb temperature of air |
| D. | The ambient air temperature |
| Answer» B. The wet-bulb temperature of air | |
| 1253. |
Evaporative air-cooler used effectively when: |
| A. | dry-bulb temperature is very close to the wet bulb temperature |
| B. | dry-bulb temperature is high and relative humidity is high |
| C. | dry-bulb temperature is low and relative humidity is high |
| D. | dry-bulb temperature is high and the relative humidity is low. |
| Answer» E. | |
| 1254. |
Two summer air-conditioning systems with non-zero by pass factor are proposed for a room with a known sensible and latent heat load. System A operates with ventilation but system B operates without ventilation. Then the: |
| A. | Bypass factor of system A must be less than the bypass factor of system B |
| B. | Bypass factor of system A must be more than the bypass factor of system B |
| C. | Apparatus dew point for system A must be lower than the apparatus dew point for system B. |
| D. | Apparatus dew point for system A must be higher than the apparatus dew point for system B. |
| Answer» D. Apparatus dew point for system A must be higher than the apparatus dew point for system B. | |
| 1255. |
In Orsat apparatus: |
| A. | Carbon dioxide is absorbed in cuprous chloride |
| B. | Carbon monoxide is absorbed in caustic potash solution |
| C. | Oxygen is absorbed in pyrogallic acid |
| D. | Nitrogen is absorbed in hot nickel chrome compound |
| Answer» D. Nitrogen is absorbed in hot nickel chrome compound | |
| 1256. |
Vapour absorption refrigeration system works using the: |
| A. | Ability of a substances to get easily condensed or evaporated |
| B. | Ability of a vapour to get compressed or expanded |
| C. | Affinity of a substance for another substance |
| D. | Absorptivity of a substance. |
| Answer» D. Absorptivity of a substance. | |
| 1257. |
Single-stage vapour compression refrigeration system cannot be used to produce ultralow temperatures because: |
| A. | Refrigerants for ultra-low temperatures are not available |
| B. | Lunbricants for ultra-low temperatures are not available |
| C. | Volumetric efficiency will decrease consider-ably |
| D. | Heat leakage into the system will be excessive |
| Answer» B. Lunbricants for ultra-low temperatures are not available | |
| 1258. |
In an ideal refrigeration (reversed Carnot) cycle, the condenser and evaporator temperatures are \[27{}^\circ C\] and \[-\,13{}^\circ C\] respectively. The COP of this cycle would be? |
| A. | 6.5 |
| B. | 7.5 |
| C. | 10.5 |
| D. | 15 |
| Answer» B. 7.5 | |
| 1259. |
Hydrogen is essential in an Electrolux refrigeration system, because: |
| A. | It acts as a catalyst in the evaporator |
| B. | The reaction between hydrogen and ammonia is endothermic in evaporator and exothermic in absorber |
| C. | The cooled hydrogen leaving the heat exchanger cools the refrigerant entering the evaporator |
| D. | It helps in maintaining a low partial pressure for the evaporating ammonia |
| Answer» E. | |
| 1260. |
Consider the following statements: In the case of a vapour compression machine, if the condensing temperature of the refrigerant is closer to the critical temperature, then there will be: (1) Excessive power consumption (2) High compression (3) Large volume flow Of these statements: |
| A. | 1, 2 and 3 are correct |
| B. | 1 and 2 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 3 are correct |
| Answer» D. 1 and 3 are correct | |
| 1261. |
When the discharge pressure is too high in refrigeration system, high pressure control is installed to: |
| A. | Stop the cooling fan. |
| B. | Stop the water circulating pump |
| C. | Regulate the flow of cooling water |
| D. | Stop the compressor. |
| Answer» D. Stop the compressor. | |
| 1262. |
In a cooling tower, "approach" is the temperature difference between the: |
| A. | Hot inlet water and cold outlet water |
| B. | Hot inlet water and WBT |
| C. | Cold outlet water and WBT |
| D. | DBT and WBT. |
| Answer» C. Cold outlet water and WBT | |
| 1263. |
For large tonnage (more than 200 tons) air- conditioning applications, which one of the following types of compressors is recommended? |
| A. | Reciprocating |
| B. | Rotating |
| C. | Centrifugal |
| D. | Screw |
| Answer» D. Screw | |
| 1264. |
When a stream of moist air is passed over a cold and dry cooling coil such that no condensation takes place, then the air stream will get cooled along the line of |
| A. | Constant wet bulb temperature |
| B. | Constant dew point temperature |
| C. | Constant relative humidity |
| D. | Constant enthalpy |
| Answer» C. Constant relative humidity | |
| 1265. |
During the adiabatic cooling of moist-air: |
| A. | DBT remains constant |
| B. | Specific humidity remains constant |
| C. | Relative humidity remains constant |
| D. | WBT remains constant |
| Answer» E. | |
| 1266. |
At 100% relative humidity, the wet bulb temperature is: |
| A. | More than dew point temperature |
| B. | Same as dew point temperature |
| C. | Less than dew point temperature |
| D. | Equal to ambient temperature. |
| Answer» D. Equal to ambient temperature. | |
| 1267. |
Consider the following statements: In psychrometry, wet-bulb temperature is a measure enthalpy of moist air, so that in the psychrometric chart: 1. The constant enthalpy lines are also constant bulb temperature lines. 2. The wet-bulb and dry bulb temperature are same at any condition 3. The wet-bulb and dry-bulb temperature are equal at saturation condition. Of these statements: |
| A. | 1 alone is correct |
| B. | 1 and 2 are correct |
| C. | 1 and 3 are correct |
| D. | 2 and 3 are correct |
| Answer» D. 2 and 3 are correct | |
| 1268. |
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to: |
| A. | Increase maximum pressure and maximum temperature. |
| B. | Reduce maximum pressure and maximum temperature. |
| C. | Increase maximum pressure and decrease maximum temperature. |
| D. | Decrease maximum pressure and Increase maximum temperature. |
| Answer» C. Increase maximum pressure and decrease maximum temperature. | |
| 1269. |
For the same maximum pressure and heat input: |
| A. | The exhaust temperature of petrol engine is more than that of diesel engine |
| B. | The exhaust temperature of diesel engine is more than that of petrol engine |
| C. | The exhaust temperature of dual cycle engine is less than that of diesel engine |
| D. | The exhaust temperature of dual cycle engine is more than that of petrol engine |
| Answer» B. The exhaust temperature of diesel engine is more than that of petrol engine | |
| 1270. |
Which one of the following events would reduce the volumetric, efficiency of a vertical compression ignition engine? |
| A. | Intel valve closing after bottom head Centre |
| B. | Inlet valve closing before bottom dead Centre |
| C. | Inlet valve opening top dead Centre |
| D. | Exhaust valve closing after top dead Centre |
| Answer» C. Inlet valve opening top dead Centre | |
| 1271. |
Match List I with List II and select the correct answer using the codes given below the lists: List-I (Elements of a complete carburettor) List-II (Rich-mixture requirement) A. Idling system 1. To compensate for dilution of charge B. Economiser 2. Fore cold starting C. Acceleration pump 3. For meeting maximum power range of operation D Choke 4. For meeting rapid opening of throttle Codes: |
| A. | A\[\to \]1, B\[\to \]2, C\[\to \]3, D\[\to \]4 |
| B. | A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 |
| C. | A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 |
| D. | A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 |
| Answer» C. A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 | |
| 1272. |
Consider the following statements regarding the advantages of fuel injection over carburetion in S.I. engines: 1. Higher power output and increased volumetric efficiency. 2. Simple and inexpensive injection equipment. 3. Longer life of injection equipment. 4. Less knocking and reduced tendency for back-fire. Select the correct answer using the codes given below: Codes: |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 2 and 3 |
| D. | 1 and 4 |
| Answer» C. 2 and 3 | |
| 1273. |
The graph shows the results of various quality levels for a component Consider the following statements: 1. Curve A shows the variation of value of component. 2. Curve B shows the variation of cost of the component. 3. Graph is called as fish bone diagram. 4. The preferred level of quality is given by line CC. 5. The preferred level of quality is given by line DD. Which of the above statements are correct? |
| A. | 1, 2 and 5 |
| B. | 1, 3 and 4 |
| C. | 2, 3 and 4 |
| D. | 1, 2 and 4 |
| Answer» E. | |
| 1274. |
Consider the following steps involved in hammer forging a connecting rod from bar stock: 1. Blocking 2. Trimming 3. Finishing 4. Fullering. 5. Edging Which of the following is the correct sequence of operations? |
| A. | 1, 4, 3, 2 and 5 |
| B. | 4, 5, 1, 3 and 2 |
| C. | 5, 4, 3, 2 and 1 |
| D. | 5, 1, 4, 2 and 3 |
| Answer» C. 5, 4, 3, 2 and 1 | |
| 1275. |
Consider the following statements related piereing and blanking: 1. Shear on the punch reduces the maximum cutting force. 2. Shear increases the capacity of the press needed. 3. Shear increases the life of the punch. 4. The total energy needed to make the cut remains unaltered due to provision of shear. Which of the above statements are correct? |
| A. | 1 and 2 |
| B. | 1 and 4 |
| C. | 2 and 3 |
| D. | 3 and 4. |
| Answer» C. 2 and 3 | |
| 1276. |
Which of the following materials are used in Grinding wheel? 1. Aluminum oxide 2. Cubic boron nitride 3. Silicon carbide. Select the correct answer using the codes given below: Codes: |
| A. | 1, 2 and 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3. |
| Answer» B. 1 and 2 | |
| 1277. |
Consider the following statements: The strength of a single point cutting tool depends upon 1. Rake angle 2. Clearance angle 3. Lip angle. Which of these statements are correct? |
| A. | 1 and 3 |
| B. | 2 and 3 |
| C. | 1 and 2 |
| D. | 1, 2 and 3. |
| Answer» E. | |
| 1278. |
Which of the following fibre materials are used for reinforcement in composite materials: 1. Glass 2. Boron carbide 3. Graphite Select the correct answer using the codes given below: Codes: |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 3 |
| D. | 1, 2 and 3. |
| Answer» B. 1 and 3 | |
| 1279. |
Consider the following statements: Polytetrafluoro-ethane is 1. A thermoplastic material. 2. Having high friction co-efficient. 3. A thermosetting material. 4. Having low friction co-efficient. 5. An electric insulator. 6. non-sticking to surfaces. Which of the above statements are correct? |
| A. | 1, 2 and 5 |
| B. | 2, 3 and 6 |
| C. | 3, 4 and 5 |
| D. | 3, 2 and 5. |
| Answer» B. 2, 3 and 6 | |
| 1280. |
Which of the following are fabricated using engineering plastics? 1. Surface plate 2. Gears 3. Guide ways for machine tools 4. Foundary patterns. Select the correct answer using the codes given below: Codes: |
| A. | 1, 2 and 3 |
| B. | 1 |
| C. | 2, 3 and 4 |
| D. | 1, 2, 3 and 4. |
| Answer» D. 1, 2, 3 and 4. | |
| 1281. |
Consider the following statements in case of beams: 1. Rate of change of shear force is equal to the rate of loading at a particular section. 2. Rate of change of bending moment is equal to the shear force at a particular section. 3. Maximum shear force in a beam occurs at a point where bending moment is either zero or bending moment changes sign. Which of the above statement is/are correct'? |
| A. | 1 alone |
| B. | 2 alone |
| C. | 1 and 2 |
| D. | 1, 2 and 3. |
| Answer» D. 1, 2 and 3. | |
| 1282. |
Consider the following statements: Thermal stress is induced in a component in general, when 1. A temperature gradient exists in the component. 2. The component is free from any restraint. 3. It is restrained to expand or contract freely. Which of the above statements is/are correct? |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 3 alone |
| D. | 2 alone. |
| Answer» D. 2 alone. | |
| 1283. |
The earliest occurrence time for event 'I' is 8 weeks and the latest occurrence time for events 'I' is 26 weeks. The earliest occurrence time for evens '2' is 32 weeks and the latest occurrence time for events '2' is 37 weeks. If the activity time is 11 weeks, then the total float will be: |
| A. | 11 |
| B. | 13 |
| C. | 18 |
| D. | 27 |
| Answer» D. 27 | |
| 1284. |
Estimated time T, and variance of the activities 'V on the critical path in a PERT new work are given in the following table: Activity \[{{\mathbf{T}}_{\mathbf{e}}}\] (days) V \[{{\left( \mathbf{days} \right)}^{\mathbf{2}}}\] a 17 4 b 15 4 c 8 1 The probability of completing the project in 43 days is: |
| A. | 15.6% |
| B. | 0.5 |
| C. | 81.4% |
| D. | 0.9 |
| Answer» D. 0.9 | |
| 1285. |
The variance \[\left( {{V}_{1}} \right)\] for critical path \[a\to b=4\] time units, \[b\to c=16\] units, \[c\to d=4\] time units, \[d\to e=1\] time unit. The standard deviation of the critical path \[a\to e\] is: |
| A. | 3 |
| B. | 4 |
| C. | 5 |
| D. | 6 |
| Answer» D. 6 | |
| 1286. |
Consider the specific speed ranges of the following types of turbines: 1, Francis 2. Kaplan 3. Pelton The sequence of their Specific speed in increasing order is: |
| A. | 1, 2, 3 |
| B. | 3, 1, 2 |
| C. | 3, 2, 1 |
| D. | 2, 3, 1. |
| Answer» C. 3, 2, 1 | |
| 1287. |
Consider the following statements regarding a torque converter: ' 1. Its maximum efficiency is less than that of the fluid coupling 2. It has two runners and a set of stationary vanes interposed between them. 3. It has two runners. 4. The ratio of secondary to primary torque is zero for the zero value of angular velocity of secondary. Which of these statements are correct? |
| A. | 1 and 2 |
| B. | 3 and 4 |
| C. | 1 and 4 |
| D. | 2 and 4 |
| Answer» E. | |
| 1288. |
Consider the following statements: A water turbine governor 1. Helps in starting and shutting down the turbo unit. 2. Controls the speed of turbine set to match it with the hydroelectric system. 3. Sets the amount of load which a turbine unit has to carry Which of these statements are correct? |
| A. | 1, 2 and 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» D. 1 and 3 | |
| 1289. |
The cavitation number of any fluid machineryis defined as \[\sigma =\frac{p-p'}{p{{v}^{2}}/2}\] (p is absolute pressure, \[\rho \]is density and v is free stream velocity) The symbol p? denotes: |
| A. | Static pressure of fluid |
| B. | Dynamic pressure of fluid |
| C. | vapour pressure of fluid |
| D. | Shear stress of fluid. |
| Answer» D. Shear stress of fluid. | |
| 1290. |
Consider the following statements regarding the volute casing of a centrifugal pump: 1. Loss of head due to change in velocity is eliminated. 2. Efficiency of the pump is increased. 3. Water from the periphery of the impeller is collected and transmitted to the delivery pipe at constant velocity. Which of these statements are correct? |
| A. | 1, 2 and 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» B. 1 and 2 | |
| 1291. |
Air cooling is used for Freon compressors whereas water jacketing is adopted for cooling ammonia compressors. This is because |
| A. | Latent heat of ammonia is higher than that of freon |
| B. | Thermal conductivity of water is higher than that of air |
| C. | Specific heat of water is higher than that of air |
| D. | Of the larger superheat from of ammonia compression cycle. |
| Answer» B. Thermal conductivity of water is higher than that of air | |
| 1292. |
The relationship between overall efficiency \[({{\eta }_{0}})\], mechanical efficiency \[{{\eta }_{mech}}\], and hydraulic efficiency \[({{\eta }_{hyd}})\] of a turbine is: |
| A. | \[{{\eta }_{0}}\,=\,{{h}_{mech}}\,\times \,{{\eta }_{hyd}}\] |
| B. | \[{{\eta }_{0}}\,=\,{{h}_{mech}}\,/\,{{\eta }_{hyd}}\] |
| C. | \[{{\eta }_{0}}\,=\,{{\eta }_{hyd}}\,/\,{{\eta }_{mech}}\] |
| D. | \[{{\eta }_{0}}\,=\,{{\eta }_{mech}}\,-\,{{\eta }_{hyd}}\] |
| Answer» B. \[{{\eta }_{0}}\,=\,{{h}_{mech}}\,/\,{{\eta }_{hyd}}\] | |
| 1293. |
The gross head available to a hydraulic power plant is 100 m. The utilized head in the runner of the hydraulic turbine is 72 m. If the hydraulic efficiency of the turbine is 90%, the pipe friction head is estimated to be: |
| A. | 20 m |
| B. | 18 m |
| C. | 16.2 m |
| D. | 1.8 m |
| Answer» C. 16.2 m | |
| 1294. |
Consider the following turbines/wheels: 1. Francis turbine 2. Pelton wheel with two or more jets 3. Pelton wheel with a single jet 4. Kaplan turbine. The correct sequence of these turbines/wheels in increasing order of their specific speeds is: |
| A. | 2, 3, 1, 4 |
| B. | 3, 2, 1, 4 |
| C. | 2, 3, 4, 1 |
| D. | 3, 2, 4, 1 |
| Answer» C. 2, 3, 4, 1 | |
| 1295. |
Which one of the following pairs of formulae represents the specific speeds of turbine and pump respectively? (Notations have their usual meanings), |
| A. | \[d\frac{N{{Q}^{1/2}}}{{{H}^{3/4}}}\] and \[\frac{N{{P}^{1/2}}}{{{H}^{5/4}}}\] |
| B. | \[\frac{N{{Q}^{1/2}}}{{{H}^{3/4}}}\] and \[\frac{N{{P}^{1/2}}}{{{H}^{3/4}}}\] |
| C. | \[\frac{N{{P}^{1/2}}}{{{H}^{5/4}}}\] and \[\frac{N{{Q}^{1/2}}}{{{H}^{5/4}}}\] |
| D. | \[\frac{N{{P}^{1/2}}}{{{H}^{3/4}}}\] and \[\frac{N{{Q}^{1/2}}}{{{H}^{5/4}}}\] |
| Answer» D. \[\frac{N{{P}^{1/2}}}{{{H}^{3/4}}}\] and \[\frac{N{{Q}^{1/2}}}{{{H}^{5/4}}}\] | |
| 1296. |
The correct sequence of the given hydraulic turbines in decreasing order of their specific speeds is: |
| A. | Pelton wheel, Francis turbine, Kaplan turbine |
| B. | Propeller turbine, Francis turbine, Pelton wheel |
| C. | Kaplan turbine, Pelton wheel, Francis turbine |
| D. | Francis turbine, Kaplan turbine, Pelton wheel. |
| Answer» C. Kaplan turbine, Pelton wheel, Francis turbine | |
| 1297. |
Hydraulic ram is a pump which works on the principle of: |
| A. | Water hammer |
| B. | Centrifugal action |
| C. | Reciprocating action |
| D. | Hydraulic press |
| Answer» B. Centrifugal action | |
| 1298. |
If \[{{\omega }_{s}}\] and \[{{\omega }_{p}}\] represent the angular velocities of driven and driving members of a fluid coupling respectively, then the slip is equal to: |
| A. | \[1-\frac{{{\omega }_{s}}}{{{\omega }_{p}}}\] |
| B. | \[\frac{{{\omega }_{s}}}{{{\omega }_{p}}}\] |
| C. | \[\frac{{{\omega }_{p}}}{{{\omega }_{s}}}\] |
| D. | \[1-\frac{{{\omega }_{p}}}{{{\omega }_{s}}}\] |
| Answer» B. \[\frac{{{\omega }_{s}}}{{{\omega }_{p}}}\] | |
| 1299. |
Consider the following pumps: 1. Centrifugal pump, single-stage 2. Centrifugal pump, multi-stage 3. Reciprocating pump 4. Jet pump The pump (s) which can be used to lift water through a suction head of 12 m from a well would include: |
| A. | 2 alone |
| B. | 1, 3 and 4 |
| C. | 4 alone |
| D. | 1 and 3 |
| Answer» D. 1 and 3 | |
| 1300. |
Consider the following data for the performance of a centrifugal pump: Speed: 1200 rpm, flow rate 30 \[l/s,\] head 5 k W If the speed is increased to 1500 rpm, the power will be nearly equal to: |
| A. | 6.5 kW |
| B. | 8.7 kW |
| C. | 9.8 kW |
| D. | 10.9 kW |
| Answer» D. 10.9 kW | |