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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.
| 2251. |
If the rotating mass of a rim type flywheel is distributed on another rim type flywheel whose radius is half the mean radius of the farmer, energy stored in the latter at the same speed will be |
| A. | Four times the first one |
| B. | Same as the first one |
| C. | One-fourth of the first one |
| D. | One and a half times the first one |
| Answer» E. | |
| 2252. |
Which one of the following sets of acceleration involved in the motion of the piston inside cylinder of a uniform rotating cylinder mechanism |
| A. | Coriolis and radial acceleration |
| B. | Radial and tangential acceleration |
| C. | Corioiis and gyroscopic acceleration |
| D. | Gyroscopic and tangential acceleration |
| Answer» E. | |
| 2253. |
Consider the following statements: Coriolis component of acceleration depends on 1. Velocity of slider. 2. Angular velocity of the link. 3. Acceleration of slider. 4. Angular acceleration of link. Of these statements: |
| A. | 1 and 2 are correct |
| B. | 1 and 3 are correct |
| C. | 2 and 4 are correct |
| D. | 1 and 4 are correct |
| Answer» B. 1 and 3 are correct | |
| 2254. |
Which of the following clutches is positive type? |
| A. | jaw |
| B. | cone |
| C. | disc |
| D. | centrifugal |
| Answer» B. cone | |
| 2255. |
In case of an isochronous governor, the value of sensitivity is: |
| A. | infinity |
| B. | zero |
| C. | one |
| D. | None of these |
| Answer» B. zero | |
| 2256. |
Cam angle is defined as the angle |
| A. | during which the follower returns to its initial position |
| B. | of rotation of the cam for a definite displacement of the follower |
| C. | through which the cam rotates during the period in which the follower remains in the highest position |
| D. | moved by the cam from the instant the follower begins to rise, till it reaches its highest position |
| Answer» C. through which the cam rotates during the period in which the follower remains in the highest position | |
| 2257. |
Which of the following is not correct procedure to increase the fatigue limit? |
| A. | Cold working |
| B. | Shot peening |
| C. | Surface decarburisation |
| D. | Under-stressing |
| Answer» D. Under-stressing | |
| 2258. |
When the lower temperature is fixed COP of a refrigerating machine can be improved by: |
| A. | Operating the machine at higher speeds |
| B. | Operating the machine at lower speeds |
| C. | Raising the higher temperature |
| D. | Lowering the higher temperature |
| Answer» E. | |
| 2259. |
A building in a cold climate is to be heated by a Carnot heat pump. The minimum outside temperature is \[-\,23{}^\circ C.\] If the building is to he kept at \[27{}^\circ C\] and heat requirement is at the rate of 30 kW, what is the minimum power required for heat pump? |
| A. | 180 k W |
| B. | 30 k W |
| C. | 6 k W |
| D. | 5 k W |
| Answer» B. 30 k W | |
| 2260. |
The deposition of frost on evaporator tubes of an air conditioner will result in: |
| A. | Decrease in heat transfer |
| B. | Increase in heat transfer |
| C. | No change in heat transfer |
| D. | Increase in capacity of evaporator |
| Answer» B. Increase in heat transfer | |
| 2261. |
In order to substantially reduce of heat from atmosphere into cold refrigerant flowing in small diameter copper lindrically wrapped around the tubes, must be: |
| A. | Higher than critical radius of insulation |
| B. | Slightly lower than critical radius of insulation |
| C. | Equal to the critical radius of insulation |
| D. | Considerably higher than critical radius of insulation |
| Answer» D. Considerably higher than critical radius of insulation | |
| 2262. |
Flash chamber is used in refrigeration for which one of the following? |
| A. | Decreasing the pressure during multistage compression |
| B. | Increasing the compressor pressure ratio |
| C. | Effective inter cooling medium for purpose of increasing COP |
| D. | Maintaining the same pressure and temperature |
| Answer» D. Maintaining the same pressure and temperature | |
| 2263. |
Consider the following statements: When a GSHF line is extended, it may strike the saturation curve at a point. This point is called: |
| A. | Effective surface temperature. |
| B. | Air saturation temperature. |
| C. | Water boiling temperature. |
| D. | Apparatus dew point. |
| Answer» C. Water boiling temperature. | |
| 2264. |
What is the cause of burn out of hermetically sealed refrigerant compressors? |
| A. | Phase to phase short because of worn insulation |
| B. | By prolonged overload operation |
| C. | By some mechanical failure |
| D. | All the above |
| Answer» B. By prolonged overload operation | |
| 2265. |
Which one of the following statements is correct? Dew point temperature of a moist air sample remains constant during: |
| A. | A sensible heating or cooling process |
| B. | An adiabatic saturation process |
| C. | A dehumidification process |
| D. | A humidification process |
| Answer» C. A dehumidification process | |
| 2266. |
The cooling loads for a building are: RSH = 100 kW (Room sensible heat) RLH = 25 kW (Room latent heat) OASH = 10 kW (Outside air sensible heat) OALH = 10 kW (Outside air latent heat) The bypass factor of the cooling coil is 0.15. What are the values of the room sensible heat factor and external sensible heat factor respectively? |
| A. | 0.72 and 0.8 |
| B. | 0.8 and 0.79 |
| C. | 0.79 and 0.8 |
| D. | 0.79 and 0.72 |
| Answer» C. 0.79 and 0.8 | |
| 2267. |
When are the wet bulb temperature and the temperature of adiabatic saturation equal? |
| A. | If Lewis number is equal to 1 |
| B. | If Praridtl number is equal to 1 |
| C. | If Schmidt number is equal to 1 |
| D. | If Sherwood number is equal to 1 |
| Answer» B. If Praridtl number is equal to 1 | |
| 2268. |
Which one eco-friendly refrigerant out of the following is used in many domestical and a air- conditioners now-a-days? |
| A. | \[R-22\] |
| B. | \[R-113\] |
| C. | \[R-123\] |
| D. | \[R-134\] |
| Answer» E. | |
| 2269. |
Where is an oil separator in vapour compression refrigeration system installed? |
| A. | Between compressor and condenser |
| B. | Between expansion valve and receiver tank |
| C. | Inside compressor machinery |
| D. | Outside compressor machinery |
| Answer» B. Between expansion valve and receiver tank | |
| 2270. |
To maintain comfort in an air conditioned space, how can a small increase in temperature be compensated? |
| A. | By humidification |
| B. | By ventilation |
| C. | By increasing air velocity |
| D. | By decreasing air velocity |
| Answer» C. By increasing air velocity | |
| 2271. |
Match List-I with List-II and select the correct answer using the code given below the lists: List-I List-II A. Bell Coleman refrigeration 1. Expansion B. Reversed Carnot cycle 2. Heat Pump C. Milk chilling plant 3. Decreases COP D. Superheating in refrigeration cycle 4. Compressor 5. Brine 6. Vortex refrigerator 7. Increases COP Codes: |
| A. | A\[\to \]1, B\[\to \]6, C\[\to \]5, D\[\to \]3 |
| B. | A\[\to \]4, B\[\to \]2, C\[\to \]3, D\[\to \]7 |
| C. | A\[\to \]1, B\[\to \]2, C\[\to \]5, D\[\to \]3 |
| D. | A\[\to \]4, B\[\to \]6, C\[\to \]3, D\[\to \]7 |
| Answer» D. A\[\to \]4, B\[\to \]6, C\[\to \]3, D\[\to \]7 | |
| 2272. |
In a Bell Coleman cycle refrigeration plant compression and expansion of air are isentropic if the temperatures of air entering and leaving the expander are 300 K and 180 K respectively, what is the coefficient of performance of the plant? |
| A. | 1.5 |
| B. | 2 |
| C. | 2.5 |
| D. | 3 |
| Answer» B. 2 | |
| 2273. |
Evaporator is used sometimes to dehumidify the air for conditioning purpose. Which is one of the following is the correct statement? In this situation the evaporator temperature should he kept: |
| A. | Lower than the cooling fluid temperature |
| B. | More than the apparatus dew point temperature |
| C. | Lower than the apparatus dew point temperature |
| D. | Lower than the boiling temperature of fluid |
| Answer» C. Lower than the apparatus dew point temperature | |
| 2274. |
When a refrigeration plant is started, the evaporator temperature of the required value. During this period, how does the compressor power requirement vary? |
| A. | It increases continuously. |
| B. | It decreases and then becomes constant |
| C. | It reaches a peak and then decreases. |
| D. | It remains constant |
| Answer» D. It remains constant | |
| 2275. |
Match List-I with List-II and select the correct answer using the codes given below the lists: List-I List-II A. Sulphur candle test 1. Propane B. Halide torch test 2. Ammonia C. Soap and water test 3. Halocarbon refrigerants D. Ammonia swab test 4. Sulphur dioxide Codes: |
| A. | A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]4 |
| B. | A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 |
| C. | A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 |
| D. | A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 |
| Answer» D. A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 | |
| 2276. |
Water in an insulated evaporative cooler evaporates at the rate of 0.003 kg/s. Air flow rate is 1 kg/s. What is the air temperature decrease if the specific heat of humid air is 1 kJ/kg. K and latent heat of water is 2500 kJ/kg? |
| A. | \[2.5{}^\circ C\] |
| B. | \[3.0{}^\circ C\] |
| C. | \[7.5{}^\circ C\] |
| D. | \[10{}^\circ C\] |
| Answer» D. \[10{}^\circ C\] | |
| 2277. |
Consider the following statements: During sensible heating 1. moisture content increases 2. dry bulb temperature and wet bulb temperature increase. 3. dew point remains constant. 4. relative humidity increases. Of these statements |
| A. | 1, 2 and 3 are correct |
| B. | 2, 3 and 4 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 2 are correct |
| Answer» D. 1 and 2 are correct | |
| 2278. |
The equivalent diameter D of a circular duct corresponding to a rectangular duct having longer side ?a? and shorter side ?b? the same velocity and pressure drop is given by: |
| A. | \[D=\frac{a+b}{ab}\] |
| B. | \[D=\frac{ab}{a+b}\] |
| C. | \[D=\frac{(a+b)}{2ab}\] |
| D. | \[D=\frac{2ab}{a+b}\] |
| Answer» E. | |
| 2279. |
Match List-I with List-II and select the correct answer using the codes given below the Lists: List-I List-II A. Freon 12 1. Centrifugal systems B. Freon 22 2. Low temperature cold storage C. Feron 11 3. Window type units D Ammonia 4. Ice plants Codes: |
| A. | A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4 |
| B. | A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4 |
| C. | A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 |
| D. | A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 |
| Answer» B. A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4 | |
| 2280. |
In on-off control refrigeration system, which one of the following expansion devices is used? |
| A. | Capillary tube |
| B. | Thermostat |
| C. | Automatic expansion valve |
| D. | Float valve |
| Answer» C. Automatic expansion valve | |
| 2281. |
Which one of the following statements is true for effective temperature, ET? |
| A. | ET increases with increase in level of activity and it decreases with increase in air velocity |
| B. | ET decreases with increase in level of activity and it increases with increase in air velocity |
| C. | ET increases with increase in level of activity and it increases with increase in air velocity |
| D. | ET decreases with increase in level of activity and decreases with increase in air velocity |
| Answer» B. ET decreases with increase in level of activity and it increases with increase in air velocity | |
| 2282. |
Consider the following statements: If moist air is adiabatically saturated in an air washer then: 1. Wet bulb temperature remains constant. 2. Relative humidity increases. 3. Dry bulb temperature decreases. 4. Humidity ratio decreases. Which of these statements are correct? |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 2, 3 and 4 |
| D. | 1, 3 and 4 |
| Answer» D. 1, 3 and 4 | |
| 2283. |
Match List-I (chemical formula of refrigerant) with List-II (Numerical Designation) and select the correct answer using the codes gives below the lists: List-I (Chemical formula of Refrigerant) List-II (Numerical Designation) A. \[N{{H}_{3}}\] 1. 12 B. \[CC{{l}_{2}}{{F}_{2}}\] 2. 22 C. \[CHCl{{F}_{2}}\] 3. 40 D. \[CC{{l}_{2}}FCCl{{F}_{2}}\] 4. 113 5. 717 Codes: |
| A. | A\[\to \]4, B\[\to \]1, C\[\to \]5, D\[\to \]2 |
| B. | A\[\to \]5, B\[\to \]3, C\[\to \]2, D\[\to \]4 |
| C. | A\[\to \]4, B\[\to \]3, C\[\to \]5, D\[\to \]2 |
| D. | A\[\to \]5, B\[\to \]1, C\[\to \]2, D\[\to \]4 |
| Answer» E. | |
| 2284. |
In system A vapours are superheated by \[10{}^\circ C\] in the evaporator while in system B vapours are superheated by \[10{}^\circ C\] in a liquid vapour regenerative heat exchanger, other conditions being the same. Then: |
| A. | C.O.P of A = COP of B |
| B. | C.O.P. of both A and B > C.O.P. of Reversed Carnot Cycle |
| C. | C.O.P. of A > C.O.P. of B |
| D. | C.O.P. of A < C.O.P. of B |
| Answer» D. C.O.P. of A < C.O.P. of B | |
| 2285. |
The throttling device used in the domestic refrigerator is: |
| A. | Internally equalized thermostatic expansion valve |
| B. | Externally equalized thermostatic expansion valve |
| C. | Automatic expansion valve |
| D. | Capillary tube |
| Answer» E. | |
| 2286. |
Match List-I with List-II and select the correct answer using the codes given below the lists: List-I List-II A. Refrigerant 11 1. \[CC{{l}_{2}}{{F}_{2}}\] B. Refrigerant 12 2. \[{{C}_{2}}C{{l}_{2}}{{F}_{4}}\] C. Refrigerant 22 3. \[CC{{l}_{3}}F\] D. Refrigerant 114 4 \[CHCl{{F}_{2}}\] 5. \[C{{H}_{2}}ClF\] Codes: |
| A. | A\[\to \]2, B\[\to \]1, C\[\to \]5, D\[\to \]3 |
| B. | A\[\to \]3, B\[\to \]4, C\[\to \]5, D\[\to \]2 |
| C. | A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2 |
| D. | A\[\to \]5, B\[\to \]1, C\[\to \]4, D\[\to \]3 |
| Answer» D. A\[\to \]5, B\[\to \]1, C\[\to \]4, D\[\to \]3 | |
| 2287. |
The power (kW) required per ton of refrigeration is \[\frac{N}{COP,}\] where COP is the coefficient of performance then N is equal to: |
| A. | 2.75 |
| B. | 3.5 |
| C. | 4.75 |
| D. | 5.25 |
| Answer» C. 4.75 | |
| 2288. |
In a certain ideal refrigeration cycle, the COP of heat pump is 5. The cycle under identical conditions running as heat engine will efficiency as: |
| A. | Zero |
| B. | 0.2 |
| C. | 1 |
| D. | 6 |
| Answer» C. 1 | |
| 2289. |
The ratio of weight of water vapour associated with unit weight of dry air to the weight of water vapour associated with unit weight of dry air saturated at the same dry-bulb temperature and pressure is known as: |
| A. | Specific humidity |
| B. | relative humidity |
| C. | Absolute humidity |
| D. | degree of saturation |
| Answer» E. | |
| 2290. |
If the measured wet-bulb temperature and the thermodynamic wet-bulb temperature are equal, than the non-dimensional number with a value of unity is the: |
| A. | Lewis number |
| B. | Prandtl number |
| C. | Schmidt number |
| D. | Sherwood number |
| Answer» B. Prandtl number | |
| 2291. |
Replacing a water cooled condenser with an air-cooled one in a vapour compression refrigeration system with constant evaporator pressure result in: |
| A. | Increase in condensation pressure |
| B. | Decrease in pressure ratio |
| C. | Increase in pressure ratio |
| D. | Increase in condensation temperature |
| Answer» E. | |
| 2292. |
Consider the following statements: In a reciprocating compressor, clearance volume is provided: 1. so that position does not hit and damage the valves 2. To account for differential thermal expansion of piston and cylinder 3. To account for machining tolerances 4. To achieve isentropic compression Which of these statements are correct? |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 1, 3 and 4 |
| D. | 2, 3 and 4 |
| Answer» C. 1, 3 and 4 | |
| 2293. |
The function of a compressor in a vapour absorption system is performed by the: |
| A. | Absorber |
| B. | Absorber and pump |
| C. | Pump and generator |
| D. | Absorber, pump and generator |
| Answer» E. | |
| 2294. |
An expansion valve is not used for reducing pressure in the: |
| A. | vapour compression refrigeration cycle |
| B. | vapour absorption refrigeration cycle |
| C. | steam-jet refrigeration cycle |
| D. | Gas refrigeration cycle |
| Answer» D. Gas refrigeration cycle | |
| 2295. |
Consider the following statements. The pressure in a capillary tube of a refrigerator decreases because: 1. Tube wall offers frictional resistance. 2. Refrigerant accelerates in the tube. 3. Tube transfer the heat. 4. Potential energy decreases Of these statements: |
| A. | 1 and 2 are correct |
| B. | 1, 2 and 3 are correct |
| C. | 2 and 4 are correct |
| D. | 3 and 4 are correct |
| Answer» B. 1, 2 and 3 are correct | |
| 2296. |
Consider the following statements: High condenser pressure in a refrigeration system can occur because: 1. The water flow rate is lower than the desired value. 2. Non-condensible gases are present in the system. 3. of accumulation of lubricating oil in condenser 4. of low charge of refrigerant in the system Of these statements: |
| A. | 1, 3 and 4 are correct |
| B. | 1, 2 and 3 are correct |
| C. | 1, 2 and 4 are correct |
| D. | 2, 3 and 4 are correct |
| Answer» E. | |
| 2297. |
Which of the following are the special features of a hermetically sealed compressor of a refrigerator? 1. The compressor may be reciprocating to rotary type. 2. No shaft seal is necessary. 3. More silent in operation. 4. COP is more than that of open compressor. Select the correct answer using the codes given below: |
| A. | 2 and 4 |
| B. | 1, 2 and 3 |
| C. | 1, 3 and 4 |
| D. | 2, 3 and 4 |
| Answer» C. 1, 3 and 4 | |
| 2298. |
A refrigerating system operating on reverse Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the exit of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is so K, then the network of compression will be (assume air as the working substance with \[{{c}_{p}}=\,\,1\,\,KJ\,per\,kg\,per{}^\circ C)\] |
| A. | 250 kJ/kg |
| B. | 200 kJ/kg |
| C. | 50 kJ/kg |
| D. | 25 kJ/kg |
| Answer» E. | |
| 2299. |
A heat pump working on a reversed carnot cycle has a COP of 5. If it works as a refrigerator taking 1 kW work input, the refrigerating effect will be: |
| A. | 1 kW |
| B. | 2 kW |
| C. | 3 kW |
| D. | 4 kW |
| Answer» E. | |
| 2300. |
During sensible cooling: |
| A. | Relative humidity remains constant |
| B. | Wet bulb temperature increases |
| C. | Specific humidity increases |
| D. | Partial pressure of vapour remains constant |
| Answer» E. | |