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 entropy __________ in an irreversible cyclic process. A. remains constant B. decreases C. increases
Last Answer : Answer: C
Description : During throttling process (a) heat exchange does not take place (b) no work is done by expanding steam (c) there is no change of internal energy of steam (d) all of the above (e) entropy decreases.
Last Answer : Answer : d
Description : On a day when the partial pressure of water vapor remains constant, what happens as the temperature rises? a. the relative humidity increases b. the relative humidity decreases c. the relative humidity remains constant d. the air would eventually become saturated
Last Answer : the relative humidity decreases
Description : The volume of a given amount of water _________ as the temperature decreases from 4˚C to 0˚C. a. decreases b. increases c. remains constant d. none of the above
Last Answer : increases
Description : An ideal gas is compressed in a cylinder so well insulated that there is essentially no heat transfer. The temperature of gas a. Remains constant b. increases c. decreases d. is basically zero
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.
Last Answer : Answer : a
Description : In an isothermal process, the internal energy (a) increases (b) decreases (c) remains constant (d) first increases and then decreases (e) first decreases and then increases.
Last Answer : Answer : c
Description : In an isothermal process, the internal energy of gas molecules (a) increases (b) decreases (c) remains constant (d) may increase/decrease depending on the properties of gas (e) shows unpredictable behaviour.
Description : Which of the following occurs in a reversible polytrophic process? a. Enthalpy remains constant b. Internal energy does not change c. Some heat transfer occurs d. Entropy remains constant
Last Answer : Some heat transfer occurs
Description : A process during which entropy remains constant is called ______ process A. Isometric B. Isochoric C. Isobaric D. Isentropic
Last Answer : Isentropic
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 : Which of the following is the other term used for enthalpy-entropy diagram? a. Enthalpy diagram b. Mollier diagram c. Steam diagram d. Entropy chart
Last Answer : Mollier diagram
Description : Calculate the entropy of steam at 60psiawith a quality of 0.8 A. 0.4274 BTU/lbm-˚R B. 0.7303 BTU/lbm-˚R C. 1.1577 BTU/lbm-˚R D. 1.2172 BTU/lbm-˚R Formula: fromthe steamtable at 60 psia: sƒ = 0.4274 BTU/lbm-˚R sƒg = 1.2172 BTU/lbm-˚R) s = sƒ + x sƒg where x = is the quality
Last Answer : 1.1577 BTU/lbm-˚R
Description : Mixture of liquid and steam of the same substance in which both are at saturation temperature. a. dry steam b. current steam c. wet steam d. aerosol
Last Answer : wet steam
Description : As we heat a gas at constant pressure, its volume a. increases b. decreases c. stays the same d. none of the above
Description : A vessel with a volume of cubic meter contains liquid water and water vapor ion equilibrium at 600 kPa. The liquid water has mass of1kg. Using the steam table, calculate the mass of the water vapor. A. 0.99kg B. 1.57 kg C ... / kg vg = 0.3157 m^3 / kg Vtot = mƒ vƒ + mg vg mg = (tot-mƒ vƒ) / vg
Last Answer : 3.16 kg
Description : A 10m^3 vessel initially contains 5 m^3 of liquid water and 5 m^3 of saturated water vapor at 100 kPa. Calculate the internal energy of the system using the steam table. A. 5 x10^5 kJ B. 8x10^5 kJ C. 1 ... 3 kJ/kg ug= 2506kJ/kg formula: Mvap = V vap/vg M liq = Vliq/ vƒ u =uƒM liq + ug M vap
Last Answer : 2 x10^6 kJ
Description : _____ is that property of a substance which remains constant if no heat enters or leaves the substance, while it does work or alters its volume, but which increases or diminishes should a small amount of heat enter or leave. a. Entrophy b. Enthalpy c. Specific Heat d. None of the above
Last Answer : Entrophy
Description : When a solid melts, a. the temperature of the substance increases. b. the temperature of the substance decreases. c. heat leaves the substance. d. heat enters the substance.
Last Answer : heat enters the substance.
Description : In a free expansion process (a) work done is zero (b) heat transfer is zero (c) both (a) and (b) above (d) work done is zero but heat increases (e) work done is zero but heat decreases.
Description : Twenty grams of ice at 0˚C melts to water at 0˚C. How much does the entropy of the 20g change in this process? a. 30.5 J/K b. 24.6 J/K c. 21.3 J/K d. 15.7 J/K
Last Answer : 24.6 J/K
Description : The entropy of water at 0°C is assumed to be A. 1 B. 0 C. -1 D. 10
Last Answer : Answer: B
Description : Which of the following laws of thermodynamic which leads to the definition of entropy? a. First law b. Second law c. Third law d. Law of conservation of energy
Last Answer : Second law
Description : A temperature scale whose zero point is absolute zero, the temperature of “0” entropy at which all molecular motion stops. a. Celsius b. Fahrenheit c. Kelvin d. Rankine
Last Answer : Kelvin
Description : As temperature goes to “0”, the entropy approaches a constant a. Zeroth Law of Thermodynamics b. First Law of Thermodynamics c. Second Law of Thermodynamics d. Third Law of Thermodynamics
Last Answer : Third Law of Thermodynamics
Description : A thermodynamic process in which entropy is conserved a. isentropic b. adiabatic c. isothermal d. polytropic
Last Answer : isentropic
Description : During the adiabatic process, which of the following is the change in entropy? a. zero b. greater than zero c. less than zero d. infinity
Last Answer : zero
Description : Entropy is the measure of: a. The internal energy of a gas b. The heat capacity of a substance c. Randomness or disorder d. The change of enthalpy of a system
Last Answer : Randomness or disorder
Description : The change that the system that undergoes from one equilibrium state to another is known as a. oath b. process c. enthalpy change d. entropy change
Last Answer : process
Description : Which law that states “Entropy of all perfect crystalline solids is zero at absolute zero temperature”? a. Zeroth law of thermodynamics b. First law of thermodynamics c. Second law of thermodynamics d. Third law of thermodynamics
Last Answer : Third law of thermodynamics
Description : Who coined the word Entropy? a. Rudolf Clausius b. Kelvin c. Gabriel Volks d. Rudolf Diesel
Last Answer : Rudolf Clausius
Description : What is the area under the curve on a temperature –entropy diagram? a. Heat b. work c. entropy d. volume
Last Answer : Heat
Description : What is the entropy of a pure substance at a temperature of absolute zero? a. unity b. zero c. infinity d. undefined
Description : What refers to the heat needed to change the temperature of the substances without changing its phases? a. Latent heat b. Sensible heat c. Specific heat d. entropy
Last Answer : Sensible heat
Description : What is the measure of the energy that is no longer available to perform useful work within the current environment? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : entropy
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 first law of thermodynamics is based on which of the following principles? a. Conservation of mass b. Conservation of energy c. Action and reaction d. The entropy-temperature relationship
Last Answer : Conservation of energy
Description : A state occurs in isentropic process a. The change in entropy is 0 b. The change in entropy is 1 c. The change in enthalpy is 0 d. The change in enthalpy is 1
Last Answer : The change in entropy is 0
Description : Regardless of the process, the change in enthalpy firm moles of ideal gas is a. Heat b. Enthalpy c. Entropy d. Density
Description : Composite property applicable to all fluids a. Entropy b. Enthalpy c. Specific Heat d. None of the above
Last Answer : Enthalpy
Description : The first law of thermodynamics is based on which of the following principles? a. conservation of mass b. the enthalpy-entropy relationship c. action – reaction d. conservation of energy
Last Answer : conservation of energy
Description : A function of state that is associated with disorder in the system and environment. a. enthalpy b. entropy c. law of diminishing return d. Lenz’ Law
Description : A ______ is a flow in which the gas flow is adiabatic and frictionless and entropy change is zero. A. Isentropic flow B. Isobaric flow C. Steady flow D. Uniform flow
Last Answer : Isentropic flow
Description : During adiabatic, internally reversible process, what is true about the change in entropy? A. It is temperature-dependent B. It is always greater than zero C. It is always zero D. It is always less than zero
Last Answer : It is always zero
Description : Entropy is transferred by ______. A. Work B. Heat C. Energy D. Work and heat
Description : What law states that entropy can be created but it cannot be destroyed? A. Zeroth law of thermodynamics B. First law of thermodynamics C. Second law of thermodynamics D. Third law of thermodynamics
Last Answer : Second law of thermodynamics
Description : The entropy change of a system during a process is equal to the net entropy transfer through the system boundary and the entropy generated within the system . This statement is known as: A. Entropy ... B. Entropy change of a system C. Entropy balance relation D. Third law of thermodynamics
Last Answer : Entropy balance relation
Description : What law provides an absolute reference point for the determination of entropy? A. Zeroth law of thermodynamics B. First law of thermodynamics C. Second law of thermodynamics D. Third law of thermodynamics