Description : Aqua ammonia is used as refrigerant in the following type of refrigeration system (a) compression (b) direct (c) indirect (d) absorption
Last Answer : Ans: d
Description : Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system (a) strong solution to weak solution (b) weak solution to strong solution (c) strong solution to ammonia vapour (d) ammonia vapour to strong solution.
Last Answer : Ans: b
Description : Absorption system normally uses the following refrigerant (a) Freon-11 (b) Freon-22 (c) C02 (d) ammonia.
Last Answer : Ans: e
Description : The evolution of heat of solution takes place in ammonia absorption plant when (a) ammonia vapour goes into solution (b) ammonia vapour is driven out of solution (c) lithium bromide mixes with ammonia (d) weak solution mixes with strong solution
Last Answer : Ans: a
Description : Cooling water is required for following equipment in ammonia absorption plant (a) condenser (b) evaporator (c) condenser and absorber (d) condenser, absorber and separator (rectifier).
Description : Ammonia-absorption refrigeration cycle requires (a) very little work input (b) maximum work input (c) nearly same work input as for vapour compression cycle (d) zero work input
Description : A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure ofabout 67 kg/cm. The refrigerant used is (a) Ammonia (b) Carbon dioxide (c) Freon (d) Brine
Description : The vapour pressure of refrigerant should be (a) lower than atmospheric pressure (b) higher than atmospheric pressure (c) equal to atmospheric pressure (d) could be anything
Description : Standard air is the: a. Mass of 1 cubic meter of dry air at 20°C and atmospheric pressure b. Mass of a cubic meter of air at atmospheric conditions c. Volume of air at ambient temperature and atmospheric pressure ... pressure at sea level or 101.325 kPa e. Volume of 1 kg of air at 15°C and 100 kPa
Last Answer : Answer: D
Description : Dry-bulb temperature is: a. The absolute temperature corresponding to the atmospheric pressure b. The same as the wet-bulb temperature if the relative humidity is less than 100% c. Not required ... d. The temperature of the air measured with an ordinary thermometer e. The dew point temperature
Description : Dew point can be best defined as the: a. Absolute temperature at which air, upon heating, will evaporate moisture b. . Percentage of moisture that air can hold at a given temperature ... to condense should the temperature drop further e. . Atmospheric pressure at which air will condense moisture
Description : With suction pressure being atmospheric, increase in delivery pressure with fixed clearance volume A. increase volumetric efficiency B. decrease volumetric efficiency C. does not change volumetric efficiency D. First increase volumetric efficiency and then decrease it
Last Answer : ANSWER : B
Description : A gas is compressed from 1 bar and 30°C to 5 bars and 30°C. Identify process and show on PV diagram.
Last Answer : Gas is compressed from (1) 1 bar 30 0C to (2) 5 bar 30 0C Temp is constant. Hence process is isothermal. P x V = Constant
Description : An R.C.C. beam of 6 m span is 30 cm wide and has a lever arm of 55 cm. If it carries a U.D.L. of 12 t per m and allowable shear stress is 5 kg/cm2 , the beam (A) Is safe in shear (B) Is safe with stirrups (C) Is safe with stirrups and inclined bars (D) Needs revision of section
Last Answer : Answer: Option D
Description : In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (a) suction of compressor (b) delivery of compressor (c) high pressure side close to receiver (d) low pressure side near receiver
Last Answer : Ans: c
Description : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Description : An important characteristic of absorption system of refrigeration is (a) noisy operation (b) quiet operation (c) very little power consumption (d) its input only in the form of heating.
Last Answer : Ans: D
Description : For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of (a) copper (b) aluminium (c) steel (d) brass
Description : In milk chilling plant, the usual secondary refrigerant is (a)ammonia (b)sodium silicate (c) glycol (d) brine
Description : Ammonia is (a) non-toxic (b) non-inflammable (c) toxic and non-inflammable (d) highly toxic and inflammable
Description : The boiling point of ammonia is (a) -100°C (b) -50°C (c) - 33.3°C (d) 33.3°C.
Description : The capacity of the compressor will be highest when its intake temperature is A. Lowest B. highest C. Atmospheric D. Unpredictable
Last Answer : ANSWER : C
Description : Which one of the following methods can be adopted to obtain isothermal compression in an air compressor? A. Increasing the weight of the compressor B. Inter-stage heating C. Atmospheric cooling D. Providing appropriate dimensions to the cylinder
Last Answer : ANSWER : A
Description : The COP of a vapour compression plant in comparison to vapour absorption plant is (a) more (b) less (c) same (d) more/less depending on size of plant
Description : Choose the wrong statement (a) Temperature of medium being cooled must be below that of the evaporator (b) Refrigerant leaves the condenser as liquid (c) All solar thermally operated absorption systems are capable only of intermittent operation (d) frost on evaporator reduces heat transfer
Description : Pick up the incorrect statement (a) lithium bromide used in vapour absorption cycle is nonvolatile (b) lithium bromide plant can't operate below 0°C (c) a separator is used in lithium ... of solution coming out of lithium bromide generator is more in comparison to that entering the generator
Description : The theoretically correct air fuel ratio of a petrol engine is of the order of A. 6:1 B. 10:1 C. 15:1 D. 20:1
Description : The theoretically correct air fuel ratio for petrol engine is of the order of a.6 : 1 b. 9 : 1 c. 12 : 1 d. 15 : 1
Last Answer : Answer d. 15:1
Description : Pressure of steam in condenser is (A) Atmospheric pressure (B) More than atmospheric pressure (C) Slightly less than atmospheric pressure (D) much less than atmospheric pressure.
Last Answer : much less than atmospheric pressure.
Description : The condition of refrigerant before entering the expansion or throttle valve, in a vapour compression system (a) dry vapour (b) wet vapour (c)liquid-vapour mixture (d) high pressure saturated liquid
Description : In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be (a) high, of the order of 25° (b) as low as possible (3 to 11°C) (c) zero (d) any value
Description : In ammonia synthesis (N2 + 3H2 = 2NH3 ), there is a decrease in total volume, hence to get high equilibrium conversion, the reaction should becarried out at (A) Low pressure (B) High pressure (C) Very high temperature (D) Atmospheric pressure; as the pressure has no effect on conversion
Last Answer : (B) High pressure
Description : In a two stage reciprocating air compressor with a suction pressure of 2 bar and delivery pressure of 8 bar the ideal intercooler pressure will be A. 10 bar B. 6 bar C. 4 bar D. 3 bar
Description : In a constant pressure process steam is generated from 10 bar and 0.8 dry condition till it become dry and saturated. Determine amount of heat added per kg of steam. From steam table at 10 bar Tsat = 179.9°C hf = 762.6 kl/kg, hg = 2776.2 kJ/kg
Last Answer : Constant pressure process Final condition of steam is dry saturated Enthalpy of dry steam = hg= hf + hfg =2776.2 KJ/Kg .Given Latent heat of vaporization = hfg = hg - hf =2776.2-762.6 =2013.6 KJ/Kg Initial condition ... hfg = 762.6+0.8 X 2013.6 =2373.48 KJ/Kg Heat added = hg-hw = 402.72 KJ/kg
Description : In a weather map, lines joining all those regions with same atmospheric pressure are called A. Bars B. Millibars C. Isobars D. Atmospheric bars
Last Answer : Isobars
Description : Common rail injection system uses injection pressures of the order a) 100-200 bar b) 200-400 bar c) 400-600 bar d) 1500 bar
Last Answer : Answer: d Explanation: Generally, common rail injection system uses injection pressures of the order 1500 bar.
Description : For obtaining high COP, the pressure range of compressor should be (a) high (b) low (c) optimum (d) any value
Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used
Description : For better COP of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be (a) small (b) high (c) equal (d) anything
Description : In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion or throttle valve (d) before entering the expansion valve
Description : A reciprocating compressor is not suitable for use as a supercharger because: A. it runs at lower rpm B. the pressure ratio is high C. volumetric efficiency is high D. it is bulky and can handle small quantity of air
Last Answer : ANSWER : D
Description : As a result of detonation in an I.C engine, following parameter attains a high value A. peak temperature B. peak pressure C. rate of pressure rise D. rate of temperature rise
Description : With EFI of diesel engines a) sharp start and stop is not possible b) very high injection pressure can be obtained c) sudden cylinder cut-off is impossible d) diagnostic properties are poor
Last Answer : Answer: b Explanation: Generally, with EFI of diesel engines very high injection pressure can be obtained.
Description : The tendency of knocking in CI engine reduces by (a) High self ignition temperature of fuel (b) Decrease in jacket water temperature (c) Injection of fuel just before TDC (d) Decrease in injection pressure
Last Answer : Ans :c
Description : Rotary compressors are used for delivering A. Small quantities of air at high pressure B. Large quantities of air at high pressure C. Small quantities of air at low pressure D. Large quantities of air at low pressure
Description : Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply ... . Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.
Description : For a two stage compressor, the ratio of diameter of low pressure cylinder to high pressure cylinder is equal to A. Square of the ratio of final pressure to initial pressure B. The ratio of ... final pressure to initial pressure D. Cube root of the ratio of final pressure to initial pressure
Description : As a result of detonation in Internal combustion engines the following parameter attains very high value. a. peak pressure b. rate of rise of pressure c. rate of rise of temperature. d. peak temperature.
Last Answer : ANSWER b. rate of rise of pressure
Description : Vapour lock is a. complete or partial stoppage of fuel supply due to vaporization of the fuel b. locking of carburetor due to high vapor pressure c. excess fuel supply to the engine d. supply of liquid fuel to the engine
Last Answer : ANSWER a. complete or partial stoppage of fuel supply due to vaporization of the fuel
Description : The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is (a) bigger (b) smaller (c) equal (d) smaller/bigger depending on capacity