If work done by an engine is equal to the heat supplied, then its efficiency is

1 Answer

Answer :

100%.

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Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ

Last Answer : ANSWER d. 973.5 kJ

Description : An engine is supplied with 4 kW of heat energy. It is found that it produce 4 kW of work. Which kind of perpetual machine it is? Which law is violated? Also describe other kind of perpetual machine you know.

Last Answer : PMM-II: A heat engine which violates Kelvin plank statement of the second law of thermodynamics is known as Perpetual Motion Machine of the second kind (PMM-II). Or 100 percent efficient machine which is ... no machine can produce energy of its own without consuming any other form of energy.

Description : The efficiency of the Otto cycle is independent of a. Heat supplied b. Compression ratio c. Ratio of specific heats d. None of the above

Last Answer : Answer a. Heat supplied

Description : Pick out the correct statement. (A) Compression ratio of an Otto engine is comparatively higher than a diesel engine (B) Efficiency of an Otto engine is higher than that of a diesel ... Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Last Answer : (B) Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio

Description : In diesel engine, the fuel is ignited by a. spark b. injected fuel c. heat resulting from compressing air that is supplied for combustion d. ignitor

Last Answer : ANSWER c. heat resulting from compressing air that is supplied for combustion

Description : The work done by a system is `8J`, when `40J` heat is supplied to it. Calculate the increases in internal energy of system.

Last Answer : The work done by a system is `8J`, when `40J` heat is supplied to it. Calculate the increases in internal energy of ... J B. 40 J C. 48 J D. `-32 J`

Description : Which of the following relations is not applicable in a free expansion process?  a. Heat is rejected to zero  b. Work done is zero  c. Change in temperature is zero  d. Heat supplied is zero

Last Answer : Change in temperature is zero

Description : The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is ... is (A) 100,000 kW (B) 160,000 kW (C) 200,000 kW (D) 320,000 kW

Last Answer : (D) 320,000 kW

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 : 2000 kJ of heat is supplied to 500 kg of ice at 0oC. If the latent heat of fusion of ice is 335 kJ/kg then the amount of ice in kg melted will be a) 1.49 b) 83.75 c) 5.97 d) None of the above

Last Answer : c) 5.97

Description : Which of the following represents the perpetual motion of the first kind  (a) engine with 100% thermal efficiency  (b) a fully reversible engine  (c) transfer of heat energy from low ... its own energy  (e) production of energy by temperature differential in sea water at different levels.

Last Answer : Answer : d

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 : In a naturally aspirated diesel engine, the air is supplied by a A. supercharger B. centrifugal pump C. movement of engine piston D. reciprocating pump

Last Answer : ANSWER : C

Description : The formula to calculate the efficiency of a heat engine is

Last Answer : W x 100

Description : Is it possible to have a heat engine with 100% efficiency? If no why?

Last Answer : No, we cannot have a heat engine that is 100% efficient. Whenever heat energy is converted into mechanical energy by a heat engine, a part of the heat energy is lost. Hence we cannot have 100% efficient.

Description : Define efficiency of a heat engine.

Last Answer : The efficiency of a heat engine is defined as the ratio of the actual work done to the heat energy consumed. It is expressed as percentage.

Description : Define heat engine efficiency. ?

Last Answer : The ratio of the amount of heat energy converted to work by a heat engine and the amount of heat energy absorbed by the engine is called the efficiency of that heat 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

Last Answer : ANSWER : B

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 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 : 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 : The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/R1

Last Answer : (A) T1/(T1-T2)

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 a Carnot heat engine operating between absolute temperatures T1 and T2(when, T1 > T2) is given by (T1- T2)/T1. The co efficient of performance (CO.P.) of a Carnot heat pump operating between T1 and T2is given by (A) T1/(T1-T2) (B) T2/(T1-T2) (C) T1/T2 (D) T2/T1

Last Answer : (B) T2/(T1-T2)

Description : For heat engine operating between two temperatures (T1>T2), what is the maximum efficiency attainable?  A. Eff = 1 – (T2/T1)  B. Eff = 1 - (T1/T2)  C. Eff = T1 - T2  D. Eff = 1 - (T2/T1)^2

Last Answer : Eff = 1 – (T2/T1)

Description : What is the highest efficiency of heat engine operating between the two thermal energy reservoirs at temperature limits?  A. Ericson efficiency  B. Otto efficiency  C. Carnot efficiency  D. Stirling efficiency

Last Answer : Carnot efficiency

Description : Which statement of the second law of thermodynamics states that no heat engine can have a thermal efficiency of 100 percent?  A. Kelvin-Planck statement  B. Clausius statement  C. Kevin statement  D. Rankine statement

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Description : What is the ideal efficiency of a reversible heat engine cyclically operating between a source temperature of 600 degrees Kelvin and a sink temperature of 150 degrees Kelvin?

Last Answer : ANSWER: 75 PERCENT

Description : The product of efficiency & heat transferred to the working fluid is? a. Net temperature change b. Net work done c. Net enthalpy change d. None of the mentioned

Last Answer : b. Net work done

Description : The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that  (a) carnot cycle can't work with saturated steam  (b) heat is supplied to water at temperature ... heat at two places  (d) rankine cycle is hypothetical  (e) none of the above.

Last Answer : Answer : b

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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

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Description : If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease

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Description : In which form is the supplied heat energy stored during change in temperature of substance? (1) Heat energy (2) Kinetic energy (3) Potential energy (4) Both kinetic and potential energy

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Description : It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of ... 3.06 10 5 (B) 6.12 10 5 (C) 7.24 10 5 (D) 9.08 10

Last Answer : (A) 3.06 × 10

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Last Answer : Specific Heat Capacity

Description : The heat supplied to the gaS at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 – T1 = Rise in temperature, and R = Gas constant)  A. mR(T2 – T1)  B. mcv(T2 – T1)  C. mcp(T2 – T1)  D. mcp(T2 + T1)

Last Answer : Answer: B

Description : When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.  A.True  B.False

Last Answer : Answer: A

Description : The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as  (a) Dual combustion cycle  (b) Diesel cycle  (c) Atkinson cycle  (d) Rankine cycle  (e) Stirling cycle.

Last Answer : Answer : c

Description : Change in enthalpy of a system is the heat supplied at  (a) constant pressure  (b) constant temperature  (c) constant volume  (d) constant entropy  (e) N.T.P. condition.

Last Answer : Answer : a

Description : In a boiler enthalpy of water supplied was 2000 kJ/kg. Enthalpy being added by fuel combustion is 3200 kJ/kg. Using first law of thermodynamics, find amount of heat supplied if steam generation rate is 10 tons per hour.

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Description : In which form is the supplied heat energy stored during change in temperature of substance? (1) Heat energy (2) Kinetic energy (3) Potential energy (4) Both kinetic and potential energy

Last Answer : Kinetic energy

Description : Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer ... (C) Temperature of the fin end (D) Constant temperature equal to that of the base

Last Answer : (D) Constant temperature equal to that of the base

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Last Answer : Ans : d

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Description : If radioisotopes of minerals are supplied to soil then which vascular tissue helps to translocate then in plant body?

Last Answer : If radioisotopes of minerals are supplied to soil then which vascular tissue helps to translocate then in plant body?

Description : Pick out the correct statement. (A) If an insoluble gas is passed through a volatile liquid placed in a perfectly insulated container, the temperature of the liquid will increase (B) A ... compound is defined as the heat of reaction leading to the formation of the compound from its reactants

Last Answer : (D) The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants

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