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
Last Answer : Ans: a
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 : The C.O.P. of a domestic refrigerator in comparison to domestic air conditioner will be (a) same (b) more (c) less (d) dependent on weather conditions
Last Answer : Ans: c
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 : In adiabatic evaporative cooling, heat transfer between chamber and surroundings is ____ A. zero B. high C. low D. none of the mentioned
Last Answer : ANSWER : A
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
Last Answer : Ans: d
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 a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above
Description : In four stroke engine which of the following is also known as power stroke a. Suction stroke b. Compression stroke c. Expansion stroke d. Exhaust stroke (Ans:c) Measurements of fuel and air ... into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on
Last Answer : ANSWER : B
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 : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above
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 : The specific fuel consumption of a petrol engine compared to diesel engine of same H.P is A. same B.more C. less D. unpredictable
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 : Washing of coal (A) Reduces its sulphur and ash content (B) Controls its ash fusibility and increases its calorific value (C) Improves its coking properties (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Moisture in freon refrigeration system causes (a) ineffective refrigeration (b) high power consumption (c) freezing automatic regulating valve (d) corrosion of whole system
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 : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Description : In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is (a) less than 2 kg (b) more than or equal to 3.65 kg (c) more than 10 kg (d) there is no such consideration
Description : Motoring test is conducted on IC engines to determine A. brake power B. indicated power C. friction power D. fuel consumption at full load
Description : An engine produces 10 kW brake power while working with a brake thermal efficiency of 30%. If the calorific value of the fuel used is 40000 kJ/kg, then what is the fuel consumption? (a) 1.5 kg/hour (b) 3 kg/hour (c) 0.3 kg/hour (d) 1 kg/hour
Last Answer : Ans :b
Description : If the performance of diesel engine of different sizes, cylinder dimensions and power rating are to be compared, which of the following parameters can be used for such comparison? (a) Swept volume (b) Air fuel ratio (c) Specific brake fuel consumption (d) Volumetric efficiency
Last Answer : Ans :c
Description : For same power output and same r, as compared to 2- stroke engines, four stroke SI engines have (a) Higher fuel consumption (b) Lower thermal efficiency (c) Highest exhaust temperatures (d) Higher thermal efficiency
Last Answer : Ans :d
Description : Scavenging is usually done to increase the a. thermal efficiency b. speed c. power output d. fuel consumption
Last Answer : ANSWER c. power output
Description : The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P. (a) more (b) less (c) equally. (d) unpredictable
Description : The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperatureconstant, will (a) increase (b) decrease (c) may increase or decrease depending on the type of refrigerant used (d) remain unaffected
Description : The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will (a) increase (b) decrease (c) remain unaffected (d) may increase or decrease depending on the type of refrigerant used
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
Description : In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect
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 : Domestic refrigerator working on vapour compression cycle uses the following type of expansion device (a) electrically operated throttling valve (b) manually operated valve (c) thermostatic valve (d) capillary tube
Description : The domestic refrigerator uses following type of compressor (a) centrifugal (b) axial (c) miniature sealed unit (d) piston type reciprocating
Description : The COP of a domestic refrigerator (a) is less than 1 (b) is more than 1 (c) is equal to 1 (d)depends upon the weather conditions.
Description : Rating of a domestic refrigerator is of the order of (a) 0.1 ton (b) 5 tons (c) 10 tons (d) 40 tons
Description : The vapour compression refrigerator employs the following cycle (a) Rankine (b) Carnot (c) Reversed Carnot. (d) Brayton
Description : There are different arguments given in favour of power sharing in a democratic political system. Which one of the following is not one of them? (1) It reduces conflict among different communities (2) ... (4) It speeds up the decision making process and improves the chances of unity of the country
Last Answer : (4) It speeds up the decision making process and improves the chances of unity of the country Explanation: Power sharing in a Democratic political System does not speeds up the decision making process and improves the chances of unity of the country.
Description : There are different arguments given in favour of power sharing in a democratic political system. Which one of the following is not one of them? (1) It reduces conflict among different communities (2) ... (4) It speeds up the decision-making process and improves the chances of unity of the country
Last Answer : (2) Majority community does not impose its will on others
Description : At lower temperatures and pressures, the latent heat of vaporization of a refrigerant (a) decreases (b) increases (c) remains same (d) depends on other factors
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
Last Answer : ANSWER : D
Description : How the efficiency of the SI engine is affected by the specific heat ratio (γ) of the working fluid? a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working ... not affected by change in specific heat ratio (γ) of the working fluid d. none of the above
Last Answer : ANSWER a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working fluid
Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream
Last Answer : (A) Incurs smaller pressure drop
Description : An ideal liquid refrigerant should (A) Not have a sub-atmospheric vapour pressure at the temperature in the refrigerator coils (B) Not have unduly high vapour pressure at the condenser temperature (C) Both (A) and (B) (D) Have low specific heat
Last Answer : (C) Both (A) and (B)
Description : Addition of silicon to cast iron (A) Promotes graphite module formation (B) Improves its ductility (C) Does not promote graphite flakes formation (D) Increases the fluidity of molten metal
Last Answer : Option D
Description : The specific fuel consumption for diesel engine is approximately A. 0.15 kg/kWh B. 0.2 kg/kWh C. 28 kg/kWh D. 0.36 kg/kWh
Description : Specific fuel consumption is defined as a. fuel consumption per hour b. fuel consumed per km. c. fuel consumed per BHP d. fuel consumed per hour per BHP
Last Answer : ANSWER d. fuel consumed per hour per BHP
Description : The specific fuel consumption per BHP hour for petrol engine is approximately a. 0.1 kg b. 0.2 kg c. 0.25 kg d. 0.35 kg
Last Answer : ANSWER c. 0.25 kg
Description : The specific fuel consumption per BHP hour for diesel engine is approximately a. 0.1 kg b. 0.2 kg c. 0.3 kg d. 0.4 kg
Last Answer : ANSWER b. 0.2 kg