Description : The cooling tower uses the phenomenon of evaporative cooling to cool warm water above the dbt of air. A. true B. false
Last Answer : ANSWER : B
Description : The formation of frost on cooling coils in a refrigerator (a) increases heat transfer (b) improves C.O.P. of the system (c) increases power consumption (d) reduces power consumption
Last Answer : Ans: c
Description : Which of the following statement is true? A. the chart is plotted for pressure equal to 760mm Hg B. the constant wbt line represents adiabatic saturation process C. the constant wbt line coincides with constant enthalpy line D. all of the mentioned
Last Answer : ANSWER : D
Description : Choose the correct statement (a) A refrigerant should have low latent heat (b) If operating temperature of system is low, then refrigerant with low boiling point should be used (c) Pre-cooling and sub-cooling bf refrigerant are same (d) Superheat and sensible heat of a. refrigerant are same
Last Answer : Ans: b
Description : Adiabatic compression is one in which A. Temperature during compression remains constant B. No heat leaves or enters the compressor cylinder during compression C. Temperature rise follows a linear relationship D. Work done is maximum.
Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat
Last Answer : (A) Loosing sensible heat
Description : The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is (A) Natural draft cooling tower (B) Induced draft cooling tower (C) Spray chamber (D) None of these
Last Answer : (C) Spray chamber
Description : Cooling towers are rated in terms of A. approach B. range C. both of the mentioned D. none of the mentioned
Last Answer : ANSWER :C
Description : In sensible heating or cooling, A. work done remains constant B. dry bulb temperature or air remains constant C. both of the mentioned D. none of the mentioned
Last Answer : ANSWER : A
Description : Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature ... release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : When humidity ratio of air ____ air is said to be dehumidified. A. increases B. decreases C. remains constant D. none of the mentioned
Description : When, H1 = Total heat of air entering the coil (heating or cooling) H2 = Total heat of air leaving the coil (heating or cooling) H3 = Total heat of air at the end of ... A. cooling and humidification B. cooling and dehumidification C. heating and humidification D. heating and dehumidification
Last Answer : ANSWER : C
Description : What is sensible cooling of air? A. the cooling in which sensible heat of air is removed in order to reduce temperature B. the cooling in which temperature of air is reduced without changing in its moisture content C. both a. and b. D. none of the above
Description : Describe any two sources of air leak in surface condenser. Also describe effect of air leak on latent heat of steam and cooling water requirements.
Last Answer : ✓ The main sources of air leakage found in condenser are given below: 1) There is leakage of air from atmosphere at the joint of the parts which are internally under a pressure less ... hence evaporation enthalpy of steam increases therefore more amount of cooling water required in the condenser.
Description : In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation. (A) Adiabatic (B) Isothermal (C) Non-adiabatic (D) None of these
Last Answer : (C) Non-adiabatic
Description : Pick out the correct statement: (A) In an isothermal system, irreversible work is more than reversible work (B) Under reversible conditions, the adiabatic work is less than isothermal work (C) ... state functions' (D) Matter and energy cannot be exchanged with the surroundings in a closed system
Last Answer : (B) Under reversible conditions, the adiabatic work is less than isothermal work
Description : Evaporative cooling process employs a combination of cooling and humidification in which the (A) Sensible heat is added (B) Sensible heat is removed and the latent heat is added (C) Latent heat is removed (D) Sensible heat is added and latent heat is removed
Last Answer : Option B
Description : Which of the following terms is used to describe animals that maintain a constant body temperature by producing heat by metabolic oxidations (muscle contractions) and losing excess heat by evaporative cooling? a) poikilotherms b) heterotherms c) homeotherms d) none of these
Last Answer : ANSWER: C -- HOMEOTHERMS
Description : A fuel with high heat release rate will (A) Require smaller combustion chamber (B) Have high calorific value (C) Have high adiabatic flame temperature (D) None of these
Last Answer : (A) Require smaller combustion chamber
Description : Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned
Last Answer : Answer: c Explanation: None.
Description : In a carburetor the level of the fuel in the float chamber as compared to the level of the main jet in the venture is A. lower B. same C. higher D. same or higher
Description : In pre-chamber and swirl type of combustion system ______________ is used. a) single hole injector b) multi hole injector c) long stem injector d) pintle nozzle
Last Answer : Answer: d Explanation: In pre-chamber and swirl type of combustion system pintle nozzle is used and not the other nozzles.
Description : In a 4 S diesel engine, the term ‘squish’ refers to the (a) Injection of fuel in the precombustion chamber (b) Discharge of gases from the precombustion chamber (c) Entry of air into the combustion chamber (d) Stripping of fuel from the core
Last Answer : Ans :c
Description : For spark ignition engine, the equivalence ratio of mixture entering the combustion chamber has values (A) for idling and for peak power conditions (B) for both idling and peak power conditions (C) for idling and for peak power conditions (D) for both idling and peak power conditions
Last Answer : ANSWER (B) for both idling and peak power conditions
Description : In a single stage reciprocating air compressor, the work done on air to compressor is from suction pressure to delivery pressure will be minimum when the compression is A. Isothermal process B. Adiabatic process C. Polytropic process D. Constant pressure process.
Description : Which one of the following is correct? A. In a multistage compressor adiabatic efficiency is less than stage efficiency B. In a multistage turbine adiabatic efficiency is less than the stage ... compressor is greater than one D. Preheat factor does not affect the multistage compressor performance
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 : When air passes through silica gel, A. it absorbs water vapour molecules B. latent heat of condensation is released C.dbt of air increases D. all of the mentioned
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
Last Answer : Ans: a
Description : Formation of frost on evaporator in refrigerator (a) results in loss of heat due to poor heat transfer (b) increases heat transfer rate (c) decreases compressor power. (d) can be avoided by proper design
Description : Identify modes of heat transfer involved applications with brief explanation. (1) Radiator of automobile (2) Condenser of domestic refrigerator.
Last Answer : Modes of heat transfer Automobile radiator-A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through ... of heat transfer plays very important deciding factor transferring heat from condenser tube to atmosphere.
Description : How does an adiabatic process compare to an isentropic process? A. Adiabatic heat transfer is not equal to zero; isentropic heat transfer is zero B. Both heat transfer = 0; isentropic: reversible ... is not equal to zero D. Both heat transfer is not equal to zero; isentropic: irreversible
Last Answer : Both heat transfer = 0; isentropic: reversible
Description : The refrigerant for a refrigerator should have (a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat
Description : Which law states, “The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings.” (1) Doppler’s Effect (2) Newton’s law of cooling (3) Kirchhoff’s Law (4) Stefan’s Law
Last Answer : (2) Newton’s law of cooling Explanation: Kirchhoff’s Law – Kirchhoff’s Law signifies that good absorbers are good emitters. Stefan’s Law – The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.
Description : Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings." (1) Doppler's Effect (2) Newton's law of cooling (3) Kirchhoff's Law (4) Stefan's Law
Last Answer : (2) Newton's law of cooling Explanation: Kirchhoff's Law - Kirchhoff's Law signifies that good absorbers are good emitters. Stefan's Law - The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.
Description : Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings"? (1) Doppler's Effect (2) Newton's law of cooling (3) Kirchhoff's Law (4) Stefan's Law
Last Answer : (2) Newton's law of cooling Explanation: Newton's Law of Cooling states that the rate of change of the temperature of an object is proportional to the difference between its own temperature and the ambient temperature.
Description : For a body cooling in a draft, the rate of heat loss is proportional to the difference in temperature between the body and its surroundings. a. Nemst Effect b. Caloric Theory c. Joule’s Law d. Newton’s Law of Cooling
Last Answer : Newton’s Law of Cooling
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).
Last Answer : Ans: d
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : One ton of the refrigeration is (a) the standard unit used in refrigeration problems (b) the cooling effect produced by melting 1 ton of ice (c) the refrigeration effect to freeze 1 ton of water at ... ice at 0°C in 24 hours (d) the refrigeration effect to produce 1 ton of ice at NTP conditions
Description : Condensing temperature in a refrigerator is the temperature (a) of cooling medium (b) of freezing zone (c) of evaporator (d) at which refrigerant gas becomes liquid
Description : One of the purposes of sub-cooling the liquid refrigerant is to (a) reduce compressor overheating (b) reduce compressor discharge temperature (c) increase cooling effect (d) ensure that only liquid and not the vapour enters the expansion (throttling) valve
Description : The bank of tubes at the back of domestic refrigerator are (a) condenser tubes (b) evaporator tubes (c) refrigerant cooling tubes (d) capillary tubes
Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above
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
Last Answer : Answer: D
Description : The horizontal line in psychrometric chart joining the change of state of air represents A. humidification B. sensible cooling or heating C. sensible cooling or heating with humidification D. sensible cooling or heating with dehumidification
Description : Cooling and dehumidification of air is done in summer air conditioning. A. true B. false
Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature
Description : In multi stage compressor, the isothermal compression is achieved by A. Employing intercooler B. By constantly cooling the cylinder C. By running compressor at very slow speed D. By insulating the cylinder
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