Description : If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of - 23°C,then the Carnot COP will be (a) 0.2 (b) 1.2 (c) 5 (d) 6
Last Answer : Ans: d
Description : Air refrigeration operates on (a) Carnot cycle (b) Reversed Carnot cycle (c) Rankine cycle (d) Brayton cycle.
Description : The vapour compression refrigerator employs the following cycle (a) Rankine (b) Carnot (c) Reversed Carnot. (d) Brayton
Last Answer : Ans: c
Description : Vapour compression refrigeration is some what like (a) Carnot cycle (b) Rankine cycle (c) reversedCamot cycle (d) reversed Rankine cycle
Last Answer : Ans: C
Description : A refrigerator is working on reversed carnot cycle between temperature of 30°C to –10°C with capacity of 10 tonnes. Calculate. (i) The COP (ii) Define ton of refrigeration (iii) Give the industrial application of refrigeration
Last Answer : (ii) Ton of refrigeration: It is defined as the quantity of heat required to be removed from 1Ton water at 0oC to get ice at 0oC in one day. (iii) Industrial applications of refrigeration ... food stuff such as meat, fruit, fruit juice, vegetables etc. 5. Ice cooling of concrete for dam.
Description : Which of the following has the minimum value of COP for a given refrigeration effect? (A) Reverse Carnot cycle (B) Ordinary vapour-compression cycle (C) Vapour-compression process with a reversible expansion engine (D) Air refrigeration cycle
Last Answer : (D) Air refrigeration cycle
Description : Most high speed compression ignition engine operate on A. dual cycle B. otto cycle C. diesel cycle D.Carnot cycle
Last Answer : ANSWER : A
Description : Which of the following cycle is used for Compression Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle
Last Answer : Answer b. Diesel cycle
Description : Which of the following cycle is used for Spark Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle
Last Answer : Answer a. Otto cycle
Description : In a morse test for a 2 cylinder, 2 S SI engine, the brake power was 9 kW. Whereas the brake power of individual cylinders with spark cut off were 4.25 kW and 3.75 kW. The mecheffic of the engine is (a) 90% (b) 80% (c) 45.5% (d) 52.5%
Last Answer : Ans :a
Description : A gas engine has a volume of 300 cc and clearance volume of 25 cc. Its volumetric efficiency is 0.8 and mech efficiency is 0.9. What is the volume of the mixture taken in per stroke? (a) 248 cc (b) 252 cc (c) 264 cc (d) 286 cc
Last Answer : Ans : c
Description : The value of COP in vapour compression cycle is usually (a) always less than unity (b) always more than unity (c) equal to unity (d) any one of the above
Last Answer : Ans: b
Description : For an engine operating on air standard Otto cycle, the clearance volume is 10% of the swept volume. The specific heat ratio of air is 1.4. The air standard cycle efficiency is a. 38.3 % b. 39.8 % c. 60.2 % d. 61.7 %
Last Answer : ANSWER d. 61.7%
Description : Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)? (A) Air cycle (B) Carnot cycle (C) Ordinary vapour compression cycle (D) Vapour compression with a reversible expansion engine
Last Answer : A) Air cycle
Description : If the compression ratio of an engine working on Otto cycle is increased from 5 to 7 the percentage increase in efficiency will be a. 2% b. 4% c. 8% d. 14%
Last Answer : ANSWER d. 14%
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Last Answer : Ans: a
Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP
Description : A diesel engine is usually more efficient than a spark ignition engine because a. Diesel being a heavier hydrocarbon, release more heat per kg than gasoline b. The air standard efficiency of diesel ... an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.
Last Answer : ANSWER c. The compression ratio of a diesel engine is higher than that of an S.I engine
Description : For same compression ratio a. Diesel cycle has lower efficiency than Otto cycle b. Diesel cycle has higher efficiency than Otto cycle c. Diesel cycle and Otto cycle have equal efficiencies d. Depends upon the load on engine
Last Answer : Answer a. Diesel cycle has lower efficiency than Otto cycle
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 : Most high-speed compression engines operate on a. diesel cycle b. Otto cycle c. dual cycle d. Carnot cycle
Last Answer : ANSWER c. dual cycle
Description : In which of the following cycle heat is added at constant pressure? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle
Description : In which of the following cycle heat is added at constant volume? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle
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 : The efficiency of a internal combustion engine normally is of the order of a. 15-20 % b. 20-25% c. 25-30% d. 30-35%
Last Answer : ANSWER d. 30-35%
Description : For obtaining high COP, the pressure range of compressor should be (a) high (b) low (c) optimum (d) any value
Description : A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%
Last Answer : Ans :c
Description : An ideal air standard Otto cycle has a compression ratio of 8.5. If the ratio of the specific heats is 1.4, then what is thermal efficiency (in percentage) of the Otto cycle? a. 57.5% b. 45.7% c. 52.5% d. 95%
Last Answer : ANSWER a. 57.5%
Description : The reason for supercharging in any engine is to be A. increase efficiency B. increase power C. effect fuel economy D. reduce weight and bulk for a given output
Last Answer : ANSWER : D
Description : Out of the following refrigeration cycles, which one has maximum COP? (A) Air cycle (B) Carnot cycle (C) Ordinary vapor compression cycle (D) Vapor compression with a reversible expansion engin
Last Answer : (B) Carnot cycle
Description : Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the (A) Two temperatures only (B) Pressure of working fluid (C) Mass of the working fluid (D) Mass and pressure both of the working fluid
Last Answer : (A) Two temperatures only
Description : The efficiency of Carnot cycle is maximum for (a) gas engine (b) well lubricated engine (c) petrol engine (d) steam engine (e) reversible engine.
Last Answer : Answer : e
Description : An actual engine is to be designed having same efficiency as the Carnot cycle. Such a proposition is (a) feasible (b) impossible (c) possible (d) possible, but with lot of sophistications (e) desirable.
Last Answer : Answer : d
Description : Carnot cycle efficiency depends upon (a) properties of the medium/substance used (b) condition of engine (c) working condition (d) temperature range of operation (e) effectiveness of insulating material around the engine.
Description : Carnot cycle has maximum efficiency for (a) reversible engine (b) irreversible engine (c) new engine (d) petrol engine (e) diesel engine.
Last Answer : Answer : a
Description : The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a ... )R = 1.5; (COP)HP = 2.5 (D) (COP)R = (COP)HP = 2.5
Last Answer : (C) (COP)R = 1.5; (COP)HP = 2.5
Description : Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2(T1 > T2) is (A) T2/(T1- T2) (B) T1/(T1- T2) (C) (T1- T2)/T1 (D) (T1- T2)/T2
Last Answer : (A) T2/(T1- T2)
Description : A Bell-Coleman cycle is a reversed of which the following cycles? a. Stirling cycle b. Joule cycle c. Carnot cycle d. Otto cycle
Last Answer : Joule cycle
Description : Which of the following is used in thermal power plant? a. Brayton cycle b. Reversed carnot cycle c. Rankine cycle d. Otto cycle
Last Answer : Rankine cycle
Description : The following cycle is used for air craft refrigeration (a) Brayton cycle (b) Joule cycle (c) Carnot cycle (d) Bell-Coleman cycle (e) Reversed-Brayton cycle.
Description : Reversed joule cycle is called (a) Carnot cycle (b) Rankine cycle (c) Brayton cycle (d) Bell Coleman cycle (e) Dual cycle.
Last Answer : Answer : c
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 : 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 : 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 : The relative coefficient of performance is (a) actual COP/theoretical COP (b) theoretical COP/actual COP (c) actual COP x theoretical COP (d) 1-actual COP x theoretical COP
Description : Supercharging of an IC engine is done so that the A. thermal efficiency increases B. power output increases C. speed of the engine increases D. power output decreases
Last Answer : ANSWER : B
Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine
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
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
Description : In a variable speed SI engine, the maximum torque occurs at the maximum (a) Speed (b) Brake power (c) Indicated power (d) Volumetric efficiency
Last Answer : Ans :d