Description : Gas turbine cycle consists of (a) two isothermals and two isentropics (b) two isentropics and two constant volumes (c) two isentropics, one constant volume and one constant pressure (d) two isentropics and two constant pressures (e) none of the above.
Last Answer : Answer : d
Description : The efficiency of Diesel cycle depends upon A. temperature limits B. pressure ratio C. compression ratio D. cut-off ratio and compression ratio
Last Answer : Answer: D
Description : The efficiency of a dual combustion cycle __________ upon cut-off ratio. A. depends B. does not depend
Last Answer : Answer: A
Description : Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle A. combustion is at constant volume B. expansion and compression are isentropic C. maximum temperature is higher D. heat rejection is lower
Description : When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency. A. zero B. 1/5 C. 4/5 D. 1
Description : The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will (a) increase (b) decrease (c) remain unchanged (d) increase/decrease depending on ap-plication (e) unpredictable. “
Last Answer : Answer : b
Description : For same compression ratio and for same heat added (a) Otto cycle is more efficient than Diesel cycle (b) Diesel cycle is more efficient than Otto cycle (c) efficiency depends on other factors (d) both Otto and Diesel cycles are equally efficient (e) none of the above.
Last Answer : Answer : a
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 : Which of the following engines was introduced by a German engineer, Nickolas Otto? a. Gasoline engine b. Diesel engine c. Gas turbine d. Thermal engine
Last Answer : Gasoline engine
Description : Which of the following engines is the most efficient? a. Gas turbine b. Diesel engine c. Carnot engine d. Gasoline engine
Last Answer : Carnot engine
Description : Which of the following is least efficient? a. Gas turbine b. Diesel engine c. Carnot engine d. Gasoline engine
Description : A simple steam engine receives steam from the boiler at 180˚C and exhausts directly into the air at 100˚C. What is the upper limit of its efficiency? a. 11.28 % b. 36.77 % c. 20.36 % d. 17.66 %
Last Answer : 17.66 %
Description : The efficiency of Joule cycle is A. greater than Carnot cycle B. less than Carnot cycle C. equal to Carnot cycle D. none of these
Last Answer : Answer: B
Description : The efficiency of Diesel cycle increases with A. decrease in cut-off B. increase in cut-off C. constant cut-off D. none of these
Description : The efficiency of Stirling cycle is __________ Carnot cycle. A. greater than B. less than C. equal to
Last Answer : Answer: C
Description : The efficiency of Diesel cycle approaches to Otto cycle efficiency when A. cut-off is increased B. cut-off is decreased C. cut-off is zero D. cut-off is constant
Description : The efficiency of Diesei cycle with decrease in cut off (a) increases (b) decreases (c) remains unaffected (d) first increases and then decreases (e) first decreases and then increases.
Description : If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle (a) more (b) less (c) equal (d) depends on other factors (e) none of the above.
Last Answer : Answer : c
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.
Description : Carnot cycle efficiency is maximum when (a) initial temperature is 0°K (b) final temperature is 0°K (c) difference between initial and final temperature is 0°K (d) final temperature is 0°C (e) initial temperature is minimum possible.
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.
Description : What is the ratio of the useful heat extracted to heating value? A. Combustion efficiency B. Phase efficiency C. Heat efficiency D. Work efficiency
Last Answer : Combustion efficiency
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.
Description : Which one is the correct relation between energy efficiency ratio (EER) and coefficient of performance (COP)? A. EER = 2.34 COP B. EER = 3.24 COP C. EER = 3.42 COP D. EER = 4.23 COP
Last Answer : EER = 3.42 COP
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
Description : Thermal efficiency is the ratio of: A. Network input to total heat input B. Network output to total heat output C. Network output to total heat input D. Network input to total heat output
Last Answer : Network output to total heat input
Description : According to Clausis statement of second law of thermodynamics (a) heat can't be transferred from low temperature source to high temperature source (b) heat can be transferred for low temperature to ... to high temperature source without the aid of external energy (e) all of the above.
Description : The ideal efficiency of a Brayton cycle without regeneration with increase ni pressure ratio will (a) increase (b) decrease (c) remain unchanged (d) increase/decrease depending on application (e) unpredictable.
Description : Open system usually encloses which of the following devices? A. Compressor B. Turbine C. Nozzle D. All of the above
Last Answer : All of the above
Description : It is used for gas turbines which operates on an open cycle where both the compression and expansion processes take place in rotating machinery. a. Dual Cycle b. Otto Cycle c. Carnot Cycle d. Brayton Cycle
Last Answer : Brayton Cycle
Description : In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state. a. Rankine Process b. Carnot Cycle c. Joule-Thomson process d. Refrigeration process
Last Answer : Joule-Thomson process
Description : An ideal gas as compared to a real gas at very high pressure occupies (a) more volume (b) less volume (c) same volume (d) unpredictable behaviour (e) no such correlation.
Description : Helium ( R= 0.4698 BTU/lbm-˚R ) is compressed isothermally from 14.7 psia and 68 ˚F. The compression ratio is 1:4. Calculate the work done by the gas. A. –1454 BTU/lbm B. -364 BTU/lbm C.-187BTU/lbm D.46.7 BTU/lbm Formula: W = RT ln (V2/V1)
Last Answer : -364 BTU/lbm
Description : To what conditions does a gas behave like an ideal gas? a. low temperature and low pressure b. low temperature and high pressure c. high temperature and low pressure d. high temperature and high pressure
Last Answer : high temperature and low pressure
Description : Which is the incorrect statement about Carnot cycle? A. It is used as the alternate standard of comparison of all heat engines. B. All the heat engines are based on Carnot cycle. C. It provides concept of maximising work output between the two temperature limits. D. all of the above
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.
Description : If a system after undergoing a series of processes, returns to the initial state then (a) process is thermodynamically in equilibrium (b) process is executed in closed system cycle (c) its entropy will ... sum of heat and work transfer will be zero (e) no work will be done by the system.
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 : What refers to the amount of heat removed from the cooled space in BTS’s for 1 watt-hour of electricity consumed? A. Cost efficiency rating B. Energy efficiency rating C. Coefficient of performance D. Cost of performance
Last Answer : Energy efficiency rating
Description : Liquid fuels have lower efficiency than solid fuels. A. True B. False
Description : Which of the following cycles has maximum efficiency (a) Rankine (b) Stirling (c) Carnot (d) Brayton (e) Joule.
Description : The efficiency of a Carnot engine depends on (a) working substance (b) design of engine (c) size of engine (d) type of fuel fired (e) temperatures of source and sink.
Description : The more effective way of increasing efficiency of Carnot engine is to (a) increase higher temperature (b) decrease higher temperature (c) increase lower temperature (d) decrease lower temperature (e) keep lower temperature constant.
Description : What is defined as the ratio of the change in temperature to the change in pressure when a real gas is throttled? A. Rankine coefficient B. Kelvin coefficient C. Maxwell-Boltzmann coefficient D. Joule-Thomson coefficient
Last Answer : Joule-Thomson coefficient
Description : The gas constant of a certain gas is the ratio of: A. Universal gas constant to molar mass B. Universal gas constant to atomic weight C. Universal gas constant to atomic number D. Universal gas constant to number of moles
Last Answer : Universal gas constant to molar mass
Description : The gas constant (R) is equal to the __________ of two specific heats. A. sum B. difference C. product D. ratio
Description : Universal gas constant is defined as equal to product of the molecular weight of the gas and (a) specific heat at constant pressure (b) specific heat at constant volume (c) ratio of two specific heats (d) gas constant (e) unity.
Description : If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as (a) free expansion (b) hyperbolic expansion (c) adiabatic expansion (d) parabolic expansion (e) throttling.