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 : 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
Last Answer : Answer: D
Description : The first law of thermodynamics may be expressed in the following equivalent a. the net heat transfer id equal to the network b. the sum of the total energy forms leaving the system boundary is ... neither be created nor destroyed but only converted from one form to another d. all of the above
Last Answer : all of the above
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 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 : 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 : 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 : Total heat of a substance is also known as (a) internal energy (b) entropy (c) thermal capacity (d) enthalpy (e) thermal conductance.
Description : Is a steady flow process at total constant pressure through a control volume for which there is no heat? a. Adiabatic Saturation Process b. Dew point c. Adiabatic Ratio d. None of the above
Last Answer : Adiabatic Saturation Process
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 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 : 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 : The efficiency of Diesel cycle depends upon A. temperature limits B. pressure ratio C. compression ratio D. cut-off ratio and compression ratio
Description : The efficiency of a dual combustion cycle __________ upon cut-off ratio. A. depends B. does not depend
Last Answer : Answer: A
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 efficiency and work ratio of a simple gas turbine cycle are A.low B.very low C.high D.very high
Last Answer : Answer: B
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 : Which of the following thermodynamic devices operates the reverse of the heat engine? a. Thermal pump b. Thermal evaporator c. Thermal condenser d. Thermal equilibrant
Last Answer : Thermal pump
Description : Which of the following best describes heat? a. The capacity to do work b. Forces times distances c. Sum of thermal and chemical energy d. An energy transfer due to temperature difference
Last Answer : An energy transfer due to temperature difference
Description : What states that thermal efficiencies of all reversible heat engines operating between the same two reservoirs are the same and that no heat engine is more efficient than a reversible one operating between the ... A. Ericson principle B. Carnot principle C. Otto principle D. Stirling principle
Last Answer : Carnot principle
Description : What is a measure of the ability of a material to conduct heat? A. Specific heat capacity B. Coefficient of thermal expansion C. Coefficient of thermal conductivity D. Thermal conductivity
Last Answer : Thermal conductivity
Description : What are the only two forms of energy interactions associated with a closed system? A. Kinetic energy and heat B. Heat transfer and work C. Thermal energy and chemical energy D. Latent energy and thermal energy
Last Answer : Heat transfer and work
Description : Calorie is a measure of (a) specific heat (b) quantity of heat (c) thermal capacity (d)entropy (e) work.
Description : Zeroth law of thermodynamics (a) deals with conversion of mass and energy (b) deals with reversibility and irreversibility of process (c) states that if two systems are both in equilibrium with a ... in thermal equilibrium with each other (d) deals with heat engines (e) does not exist.
Last Answer : Answer : c
Description : Which of the following items is not a path function (a) heat (b) work (c) kinetic energy (d) vdp (e) thermal conductivity.
Last Answer : Answer : e
Description : A manufacturer claims to have a heat engine capable of developing 20 h.p. by receiving heat input of 400 kcal/mt and working between the temperature limits of 227° C and 27° C. His claim is ( ... be possible with lot of sophistications (d) cost will be very high (e) theroretically possible.
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 ratio of the weight of a substance to the weight of some standard substance is called? a. Specific Heat b. Specific Gravity c. Isothermal d. Specific Weight
Last Answer : Specific Gravity
Description : Specific heat ratio is always a. > 1 b. < 1 c. = 1 d. none of the above
Last Answer : > 1
Description : The ratio of the change in energy in the form of the heat a. relative density b. specific heat c. specific gravity d. none of the above
Last Answer : specific heat
Description : The coefficient of performance (COP) is the ratio between the: A. Power consumption in watts and heat absorbed per hour B. Heat absorbed per hour and the power consumption in watts C. Work required and the absorbed heat D. Absorbed heat and work required
Last Answer : Absorbed heat and work required
Description : The ratio of specific heat at constant pressure (Cp) and specific heat at constant volume (cv) is A. equal to one B. less than one C. greater than one D. none of these
Last Answer : Answer: C
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 : The index of compression n tends to reach ratio of specific heats y when (a) flow is uniform and steady (b) process is isentropic (c) process is isothermal (d) process ... specific heat does not change with temperature (e) process is isentropic and specific heat changes with temperature.
Description : What is known as the total heat and heat content at various times in the history? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : enthalpy
Description : The concrete roof of a house is 10 m by 8 m and 10 cm thick (4"). Estimate the total heat the roof would absorb over the 12 day? a. 1.3 x 108 J b 2.3 x 108 J c. 3.3 x 108 J d. 4.3 x 108 J formula: ΔQ = ΔQ/Δtx Δt
Last Answer : 1.3 x 108 J
Description : According to first law of thermodynamics (a) work done by a system is equal to heat transferred by the system (b) total internal energy of a system during a process remains constant ( ... , enthalpy and entropy during a process remain constant (d) total energy of a system remains constant
Description : The ratio of the mass of vapor to the total mass of the mixture is called ______. A. Vapor ratio B. Vapor content C. Vapor index D. Quality
Last Answer : Quality
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 : Liquid fuels have lower efficiency than solid fuels. A. True B. False
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
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
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 : Which of the following cycles has maximum efficiency (a) Rankine (b) Stirling (c) Carnot (d) Brayton (e) Joule.
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.
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.
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 : 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.