The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called a. net efficiency b. efficiency ratio c. relative efficiency d. overall efficiency

The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called  a. net efficiency b. efficiency ratio  c. relative efficiency  d. overall efficiency  
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ANSWER  c. relative efficiency
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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%

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%

Ratio of actual indicated work to hypothetical indicated work in a steam engine is the (a) Indicated thermal efficiency (b) Friction factor (c) Mechanical efficiency (d) Diagram factor

Description : Ratio of actual indicated work to hypothetical indicated work in a steam engine is the (a) Indicated thermal efficiency (b) Friction factor (c) Mechanical efficiency (d) Diagram factor

Last Answer : Ans : d

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 cycle is higher than the Otto cycle, at a fixed compression ratio c. The compression ratio of a diesel engine is higher than that of an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.

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

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 %

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%

The thermal efficiency of a diesel cycle having fixed compression ratio with increase in cut-off ratio will a. increase b. decrease c. independent d. increase or decrease depending upon other factors

Description : The thermal efficiency of a diesel cycle having fixed compression ratio with increase in cut-off ratio will a. increase b. decrease c. independent d. increase or decrease depending upon other factors

Last Answer : ANSWER b. decrease

The ratio of indicated power to shaft power of the engine required to drive the compressor is called A. Compressor efficiency B. Volumetric efficiency C. Isothermal efficiency D. Mechanical efficiency

Description : The ratio of indicated power to shaft power of the engine required to drive the compressor is called A. Compressor efficiency B. Volumetric efficiency C. Isothermal efficiency D. Mechanical efficiency

Last Answer : ANSWER : D

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 to find the relative humidity d. The temperature of the air measured with an ordinary thermometer e. The dew point temperature

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

Last Answer : Answer: D

Wet-bulb temperature is: a. The temperature indicated by a thermometer whose bulb covered by a water-wetted wick and exposed to a rapidly moving stream of air b. The same as the dry-bulb temperature if the relative humidity is less than 100% c. The dew point temperature d. Always less than the dry-bulb temperature e. Not required to find the relative humidity

Description : Wet-bulb temperature is: a. The temperature indicated by a thermometer whose bulb covered by a water-wetted wick and exposed to a rapidly moving stream of air b. The same as the dry-bulb ... point temperature d. Always less than the dry-bulb temperature e. Not required to find the relative humidity

Last Answer : Answer: A

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 cycle is 1800 kJ/kg, then work output per cycle per kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ

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

What is defined as the ratio of the net electrical power output to the rate of fuel energy input?  A. Combustion efficiency  B. Thermal efficiency  C. Overall efficiency  D. Furnace efficiency

Description : What is defined as the ratio of the net electrical power output to the rate of fuel energy input?  A. Combustion efficiency  B. Thermal efficiency  C. Overall efficiency  D. Furnace efficiency

Last Answer : Overall efficiency

In a variable speed SI engine, the maximum torque occurs at the maximum (a) Speed (b) Brake power (c) Indicated power (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

The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure

Description : The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure

Last Answer : ANSWER : D

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%

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%

What is the relation between compression ratio (rk) and the efficiency of the Otto cycle? a. efficiency decreases with increase in compression ratio b. efficiency increases with increase in compression ratio c. efficiency is not affected by change in compression ratio d. none of the above

Description : What is the relation between compression ratio (rk) and the efficiency of the Otto cycle? a. efficiency decreases with increase in compression ratio b. efficiency increases with increase in compression ratio c. efficiency is not affected by change in compression ratio d. none of the above

Last Answer : ANSWER b. efficiency increases with increase in compression ratio

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

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

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

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

In electronic fuel injection, there is improvement in the _____________ efficiency due to comparatively less resistance in the intake manifolds which will cause less pressure losses. a) mechanical b) volumetric c) overall d) none of the mentioned

Description : In electronic fuel injection, there is improvement in the _____________ efficiency due to comparatively less resistance in the intake manifolds which will cause less pressure losses. a) mechanical b) volumetric c) overall d) none of the mentioned

Last Answer : Answer: b Explanation: In electronic fuel injection, there is improvement only in the volumetric efficiency due to comparatively less resistance in the intake manifolds which will cause less pressure losses and no other efficiencies are hindered.

The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.

Description : The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.

Last Answer : ANSWER (c) two constant volume processes and two constant entropy processes

Air standard cycle uses ____ as a working medium. a. Perfect gas b. Real gas c. Ideal gas d. Natural gas

Description : Air standard cycle uses ____ as a working medium. a. Perfect gas b. Real gas c. Ideal gas d. Natural gas

Last Answer : ANSWER a. Perfect gas

Relative humidity is a) the ratio of water vapour in the air compared to the total amount water vapour the air could contain at a given temperature b) equal to the dry bulb temperature divided by the wet bulb temperature c) equal to the wet bulb temperature divided by the dry bulb temperature d) the ratio of the mass of water vapour divided by the mass of dry air e) the ratio of the mass of water vapour divided by the mass of wet air

Description : Relative humidity is a) the ratio of water vapour in the air compared to the total amount water vapour the air could contain at a given temperature b) equal to the dry bulb temperature divided by the wet bulb ... of dry air e) the ratio of the mass of water vapour divided by the mass of wet air

Last Answer : ANSWER : A

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

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

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

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

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

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

Thermal efficiency of an internal combustion engine on weak mixture is a. higher b. lower c. unaffected d. unpredictable

Description : Thermal efficiency of an internal combustion engine on weak mixture is a. higher b. lower c. unaffected d. unpredictable

Last Answer : ANSWER a. higher

The thermal efficiency of a diesel engine is of the order of a. 92% b. 68% c. 34% d. 25%

Description : The thermal efficiency of a diesel engine is of the order of a. 92% b. 68% c. 34% d. 25%

Last Answer : ANSWER c. 34%

Scavenging is usually done to increase the a. thermal efficiency b. speed c. power output d. fuel consumption

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

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

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

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 : 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

Which one of the following statement is not correct for the volumetric efficiency of a reciprocating air compressor? A. It decreases with increase in ambient temperature B. It increases with decrease in pressure ratio C. It increases with decrease in clearance ratio D. It decreases with increases in delivery pressure

Description : Which one of the following statement is not correct for the volumetric efficiency of a reciprocating air compressor? A. It decreases with increase in ambient temperature B. It increases with ... It increases with decrease in clearance ratio D. It decreases with increases in delivery pressure

Last Answer : ANSWER : A

Which one of the following statements are correct for reciprocating air compressor? A. Its volumetric efficiency increases with increasing clearance ratio B. Its volumetric efficiency increases with pressure ratio C. Its volumetric efficiency does not vary with change in clearance ratio and pressure ratio D. Its volumetric efficiency decreases with increasing clearance ratio and pressure ratio

Description : Which one of the following statements are correct for reciprocating air compressor? A. Its volumetric efficiency increases with increasing clearance ratio B. Its volumetric efficiency increases ... ratio D. Its volumetric efficiency decreases with increasing clearance ratio and pressure ratio

Last Answer : ANSWER : D

The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of? a) compactness of the plant b) simplicity of the plant c) complexity of the plant d) expanse of the plant

Description : The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of? a) compactness of the plant b) simplicity of the plant c) complexity of the plant d) expanse of the plant

Last Answer : c) complexity of the plant

Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP ofreversed Carnot cycle (a) 1.25 (b) 0.8 (c) 0.5 (d) 0.25

Description : Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP ofreversed Carnot cycle (a) 1.25 (b) 0.8 (c) 0.5 (d) 0.25

Last Answer : Ans: d

Which of the following quantities has the GREATEST influence on the overall efficiency of a conventional (Rankine cycle) electric generating station burning fossil fuels? w) steam temperature at the steam turbine inlet x) net heating value of the fuel y) steam pressure at the steam turbine inlet z) pounds of ash and sulfur per pound of fuel

Description : Which of the following quantities has the GREATEST influence on the overall efficiency of a conventional (Rankine cycle) electric generating station burning fossil fuels? w) steam temperature at the steam turbine ... pressure at the steam turbine inlet z) pounds of ash and sulfur per pound of fuel 

Last Answer : ANSWER: W -- STEAM TEMPERATURE AT THE STEAM TURBINE INLET 

The ratio of partial pressure of water vapour in a mixture to the saturation pressure of water at the same temperature of the mixture is called as A. humidity B. partial humidity C. specific humidity D. relative humidity

Description : The ratio of partial pressure of water vapour in a mixture to the saturation pressure of water at the same temperature of the mixture is called as A. humidity B. partial humidity C. specific humidity D. relative humidity

Last Answer : ANSWER : D

What is the degree of saturation? A. the ratio of the actual relative humidity to the saturated specific humidity at the same temperature B. the ratio of the actual specific humidity to the saturated specific humidity at the same temperature C. the ratio of the saturated specific humidity to the actual specific humidity at the same temperature D. none of the above

Description : What is the degree of saturation? A. the ratio of the actual relative humidity to the saturated specific humidity at the same temperature B. the ratio of the actual specific humidity to the ... specific humidity to the actual specific humidity at the same temperature D. none of the above

Last Answer : ANSWER : B

The accumulation of carbon in a cylinder results in increase of A. clearance volume B. volumetric efficiency C. ignition time D. effective compression ratio

Description : The accumulation of carbon in a cylinder results in increase of A. clearance volume B. volumetric efficiency C. ignition time D. effective compression ratio

Last Answer : ANSWER : D

In a centrifugal compressor, an increase in speed at a given pressure ratio causes A. Increase in flow B. Decrease in flow C. Increase in efficiency D. Increase in flow and decrease in efficiency

Description : In a centrifugal compressor, an increase in speed at a given pressure ratio causes A. Increase in flow B. Decrease in flow C. Increase in efficiency D. Increase in flow and decrease in efficiency

Last Answer : ANSWER : D

Volumetric efficiency of a compressor without clearance volume A. Increases with increase in compression ratio B. Decreases wit increase in compression ratio C. Not dependent upon compression ratio D. Unpredictable

Description : Volumetric efficiency of a compressor without clearance volume A. Increases with increase in compression ratio B. Decreases wit increase in compression ratio C. Not dependent upon compression ratio D. Unpredictable

Last Answer : ANSWER : C

For a multistage compressor, the polytropic efficiency is A. the efficiency of all stages combined together B. the efficiency of one stage C. Constant throughout for all the stages D. a direct consequence of the pressure ratio

Description : For a multistage compressor, the polytropic efficiency is A. the efficiency of all stages combined together B. the efficiency of one stage C. Constant throughout for all the stages D. a direct consequence of the pressure ratio

Last Answer : ANSWER : C

In a centrifugal compressor an increase in speed at a given pressure ratio causes A. Increase in flow and increase in efficiency B. Increase in flow and decrease in efficiency C. Decrease in flow and increase in efficiency D. Decrease in flow and decrease in efficiency

Description : In a centrifugal compressor an increase in speed at a given pressure ratio causes A. Increase in flow and increase in efficiency B. Increase in flow and decrease in efficiency C. Decrease in flow and increase in efficiency D. Decrease in flow and decrease in efficiency

Last Answer : ANSWER : B

The accumulation of carbon in a cylinder results in increase of a. clearance volume b. volumetric efficiency c. ignition time d. effective compression ratio

Description : The accumulation of carbon in a cylinder results in increase of a. clearance volume b. volumetric efficiency c. ignition time d. effective compression ratio

Last Answer : ANSWER d. effective compression ratio

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 fluid b. the efficiency of the engine decreases with increase in specific heat ratio (γ) of the working fluid c. the efficiency of the engine does not affected by change in specific heat ratio (γ) of the working fluid d. none of the above

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

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 : 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

Last Answer : Ans: a

One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice (a) in 1 hour (b) in 1 minute (c) in 24 hours (d) in 12 hours

Description : One ton of refrigeration is equal to the refrigeration effect corresponding to melting of 1000 kg of ice (a) in 1 hour (b) in 1 minute (c) in 24 hours (d) in 12 hours

Last Answer : Ans: c

At any point on the saturation curve in psychometric chart, the dry bulb temperature is always A. less than the corresponding wet bulb temperature B. more than the corresponding wet bulb temperature C. equal to the corresponding wet bulb temperature D. cannot predict

Description : At any point on the saturation curve in psychometric chart, the dry bulb temperature is always A. less than the corresponding wet bulb temperature B. more than the corresponding wet bulb temperature C. equal to the corresponding wet bulb temperature D. cannot predict

Last Answer : ANSWER : C

A 4S diesel engine, when running at 2000 rpm has an injection duration of 1.5 ms.What is the corresponding of the crank angle in degrees? (a) 18° (b) 9° (c)36° (d) 15°

Description : A 4S diesel engine, when running at 2000 rpm has an injection duration of 1.5 ms.What is the corresponding of the crank angle in degrees? (a) 18° (b) 9° (c)36° (d) 15°

Last Answer : Ans :a

Air filtration in a furnace (A) Reduces its thermal efficiency (B) Is indicated by flame sting out (C) Increases the flue gas temperature (D) None of these

Description : Air filtration in a furnace (A) Reduces its thermal efficiency (B) Is indicated by flame sting out (C) Increases the flue gas temperature (D) None of these

Last Answer : (A) Reduces its thermal efficiency

What is the relative humidity for a saturated air? A. 0% B. 50% C. 100% D. cannot say

Description : What is the relative humidity for a saturated air? A. 0% B. 50% C. 100% D. cannot say

Last Answer : ANSWER : C

The term "relative humidity" applies to a) the percentage of moisture in the air as compared to the amount of moisture the air can hold at a specific temperature b) the weight of the moisture in the air c) the dryness fraction of the air d) the amount of moisture in the air e) the amount of humidity in the air

Description : The term "relative humidity" applies to a) the percentage of moisture in the air as compared to the amount of moisture the air can hold at a specific temperature b) the weight of the moisture in the air c) ... of the air d) the amount of moisture in the air e) the amount of humidity in the air

Last Answer : ANSWER : A

When the rate of evaporation of water is zero, the relative humidity of the air is A. 0% B. 100% C. 50% D. unpredictable

Description : When the rate of evaporation of water is zero, the relative humidity of the air is A. 0% B. 100% C. 50% D. unpredictable

Last Answer : ANSWER : B