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 : 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 : 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 : The efficiency of a dual combustion cycle __________ upon cut-off ratio. A. depends B. does not depend
Last Answer : Answer: A
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 : 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 : 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.
Last Answer : Answer : e
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 : Heat engine deriving its power from the energy liberated by the explosion of a mixture of some hydrocarbon, in a gaseous or vaporized form. a. Dual Combustion Engine b. Internal Combustion Engine c. External Combustion Engine d. None of the above
Last Answer : Internal Combustion Engine
Description : Turndown ratio of a burner gives an idea of the __________ in the furnace. (A) Range of fuel firing rates (B) Volume of the combustion chamber (C) Maximum heat input rate only (D) Minimum heat input rate only
Last Answer : (A) Range of fuel firing rates
Description : What refers to the rate of thermal radiation emitter per unit area of a body? A. Thermal conductivity B. Absorptivity C. Emissivity D. Emissive power
Last Answer : Emissive power
Description : What is defined as the force per unit area? A. Pressure B. Energy C. Work D. Power
Last Answer : Pressure
Description : Utilizing the answer to the previous problem, estimate the overall or average increase in temperature ( ΔT) of the concrete roof from the energy absorbed from the sun during a12hour day. Assume that all of the radiation absorbed goes into ... °C b. 8.9°C c. 9.9°C d. 10.9°C formula: ΔQ = m c ΔT
Last Answer : 7.9 °C
Description : Defined as the ratio of weight of dry steam to the weight of stuff. a. dryness fraction b. Vaporization c. fusion d. super heated steam
Last Answer : dryness fraction
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 : 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 efficiency of Diesel cycle depends upon A. temperature limits B. pressure ratio C. compression ratio D. cut-off ratio and compression ratio
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 : 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 : What happens to the internal energy of water at reference temperature where enthalpy is zero? a. Becomes negative b. Becomes positive c. Remains constant d. Cannot be defined
Last Answer : Becomes negative
Description : What is defined as the energy required to raise the temperature of a unit mass of a substance by one degree? A. Latent heat of fusion B. Molar heat C. Specific heat capacity D. Specific heat
Last Answer : Specific heat
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 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 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 : What is the internal energy associated with the phase of a system called? A. Chemical energy B. Latent energy C. Phase energy D. Thermal energy
Last Answer : Latent energy
Description : Total heat of a substance is also known as (a) internal energy (b) entropy (c) thermal capacity (d) enthalpy (e) thermal conductance.
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.
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 : Thermal power plant works on (a) Carnot cycle (b) Joule cycle (d) Rankine cycle (d) Otto cycle (e) Brayton cycle.
Description : What states that the net change in the total energy of the system during a process is equal to the difference between the total energy entering and the total energy leaving the system during ... Conservation of energy principle C. Second law of thermodynamics D. Conservation of mass principle
Last Answer : Conservation of energy principle
Description : What states that the net mass transfer to or from a system during a process is equal to the net change in the total mass of the system during that process? A. Third law of thermodynamics B. Conservation of energy principle C. Second law of thermodynamic D. Conservation of mass principle
Last Answer : Conservation of mass principle
Description : Which of the following best describes both Stirling and Ericson engines? a. Internal combustion engine b. External combustion engine c. Diesel cycle d. Rankine cycle
Last Answer : External combustion engine
Description : What refers to the minimum temperature at which combustion can be sustained? A. Burn temperature B. Kindle temperature C. Spark temperature D. Ignition temperature
Last Answer : Ignition temperature
Description : Producer gas is obtained by A. partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast B. carbonisation of bituminous coal C. passing steam over incandescent coke D. passing air and a large amount of steam over waste coal at about 650°C
Description : The dual combustion cycle consists of one constant pressure, two constant volume and two isentropic processes. A. Agree B. Disagree
Description : 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
Last Answer : ANSWER c. relative efficiency
Description : The blast furnace gas is a byproduct in the production of pig iron in the blast furnace. A. Yes B. No
Description : Calculate the power output in horsepower of an 80-kg man that climbs a flight of stairs 3.8 m high in 4.0 s. a) 744.8 hp b) 0.998 hp c) 746 hp d) 1.998 hp Formula: Power = Fd/t = mgh/t F = W = mg d = h
Last Answer : 0.998 hp
Description : The state of a thermodynamic system is always defined by its: a. Absolute temperature b. process c. properties d. temperature and pressure
Last Answer : properties
Description : What is defined as the quantity of heat needed to raise the temperature of one kilogram of water by one degrees Celsius? a. Kilojoule b. Btu c. Kilocalorie d. Latent heat
Last Answer : Kilocalorie
Description : The compressibility factor, x, is used for predicting the behavior of nonideal gases. How is the compressibility ty factor defined relative to an ideal gas? (subscript c refers to critical value) A. ... compressibility factor, x, is an dimensionless constant given by pV=zRT. Therefore z = pV / RT
Last Answer : z = pV/ RT
Description : _________ is defined as that equivalent to the pressure due to a column of mercury 76cm long. a. surface pressure b. gage pressure c. standard atmospheric pressure d. isobaric pressure
Last Answer : standard atmospheric pressure
Description : What is defined as the direct conversion of a substance from the solid to the vapor state or vice versa without passing the liquid state? A. Condensation B. Vaporization C. Sublimation D. Cryogenation
Last Answer : Sublimation
Description : What is defined as a process during which a fluid flows through a control volume steadily? A. Transient-flow process B. Steady and uniform process C. Uniform-flow process D. Steady-flow process
Last Answer : Steady-flow process
Description : What is defined a region in space chosen for study? A. Surroundings B. System C. Boundary D. Volume
Last Answer : System