# Shared Flashcard Set

## Details

Physics Thermodynamics
36
Physics
11/28/2010

Term
 Thermal conductivities of glass and fiberglass are dramatically different because of ________________thermal conductivity of air.
Definition
 Low
Term
 Several days after a snowstorm, the roof on Jones' house is uniformly covered with snow,whereas on Smith's house next door the snow has completely melted off. A likely reasonfor this is that Jones' house has ____________ roof insulation than does Smith's.
Definition
 better
Term
 (T/F)In a composite slab made of two layers of different materials, the heat flow rate throught theslab is the sum of the heat flow rates through individual layers.
Definition
 False
Term
 The insulating value of a double-glazed window may ____________ when the spacing is made togreat because of the ____________ of air in the space between the two panes of glass.
Definition
 decrease, convection
Term
 (T/F)A constant-volume gas thermometer measures the pressure of the gas and converts it intoabsolute temperature in Kelvins.
Definition
 True
Term
 A constant-volume gas thermometer measures the (absolute/gauge) pressure of the gas, rather thanits (absolute/gauge) pressure, and is more similar to a barometer than to a pressure gauge in thisrespect.
Definition
 absolute, gauge
Term
 A properly functioning thermometer measures (the object / its own) temperature.
Definition
 Its own
Term
 A thermometer put in direct sunlight is likely to show temperature _____________ than thetemperature of air around the thermometer.
Definition
 Higher
Term
 For a good heat radiator it is advantageous to have a __________ value of ____________ of the surface.
Definition
 high, emissivity
Term
 In the van der Walls equation of state,(p +an2V2)(V - nb) = nRT, the term nb accounts for the fact that a real gas occupies ___________ volume than anideal gas at the same temperature and pressure.
Definition
 More
Term
 W is positive when the work is done _______ the system, and not _________ the system.
Definition
 by the system, not on the system
Term
 A quasi-static process, which begins and ends at the same temperature, is not necessarily _________________.
Definition
 Isothermal
Term
 (T/F) If two identical gas-cylinder systems are taken from the same initial state to the same final state, thedifference between the heat obtained by a given system and the work done by this system is necessarilythe same for the two systems.
Definition
 True
Term
 (T/F)The equation Q = ΔU+W applies to both reversible and irreversible processes.
Definition
 True
Term
 To say that Q is (positive/negative) in some process is the same as saying that the system obtains from the outsideworld a net positive amount of energy due to (temperature/volume/pressure) difference alone.
Definition
 Positive, Temperature
Term
 If ice and water have been together in a glass for a long time, they both should have a temperature of _________________.
Definition
 Zero degrees celcius
Term
 (T/F)If a system goes from state 1 to state 2 in any quasi-static process, the molar specific heat, C, iscalculated as C = ΔU/(nΔT), where ΔU and ΔT are, respectively, the differences in the internal energyand temperature between the two states and n is the number of moles in the gas.
Definition
 False
Term
 In the van der Walls equation of state,(p +an2V2)(V - nb) = nRT, the term an2/V2 is introduced to account for ________________________.
Definition
 Attractive interaction between gas molecules
Term
 According to the kinetic theory of the ideal gas, if a molecule doubles its mass (while all otherparameters remain the same), its contribution to the gas pressure ________________.
Definition
 Also Doubles
Term
 Isothermal contraction of an ideal gas can be described by the equation _____________.
Definition
 Q = W
Term
 (T/F) According to the kinetic theory of the ideal gas, if all molecules of the gas double their speeds and thelength of the box containing the gas doubles as well (while other dimensions of the box and the mass ofthe gas molecules remain the same), the pressure of the gas remains unchanged.
Definition
 False
Term
 (T/f)Transfer of heat from a warmer to cooler object is an irreversible process.
Definition
 True
Term
 Molar specific heat of a gas at constant volume can be calculated as R/2 times the number of activated________________ of a molecule of the gas, where R is the universal gas constant.
Definition
 Degrees of Freedom
Term
 (T/F) In Quasi-Static Adiabatic Expansion of ideal gas, the internal enargy of the gas is converted into workwith 100% efficiency .
Definition
 True
Term
 Colder water supplied to the cooling system of a power plant (which uses natural gas as the fuel) isexpected to ________________ of the power plant.
Definition
 increase the efficiency
Term
 (T/F)The amount of work done by a heat engine in one Carnot cycle is the sum of works during the adiabaticexpansion and adiabatic contraction.
Definition
 False
Term
 A gas of very complicated molecules each with many degrees of freedom would have its specific heatratio, γ, _________________.
Definition
 Very close to 1
Term
 When a heat engine works between two reservoirs with temperatures Th and Tc, the amount of work ___________, but the ratio of the work done to the heat obtained from the hotreservoir is ________________ by Th and Tc.
Definition
 Can Differ, Completely Defined
Term
 In the Carnot cycle of a refrigerator, the stage when heat is extracted from the cold reservoir is _______________.
Definition
 Isothermal Expansion
Term
 When an ideal gas is expanded in volume at constant pressure, the average kinetic energy of the gasmolecules ________________.
Definition
 Increases.
Term
 (T/F)If the temperture of the hot reservoir stays unchanged, COP of a refrigerator increases when thetemperature cold reservoir decreases.
Definition
 False. COP decreases when the temp of cold reservoir decreases.
Term
 (T/F)A refrigerator left in a kitchen with an open door would not cool the air in the kitchen in the long run.
Definition
 True
Term
 The coefficient of performance of a refrigerator (is/is not) not limited from above.
Definition
 Is not
Term
 A Carnot-cycle heat pump uses work W and delivers heat Q into a house, where W is always ________________Q.
Definition
 less than
Term
 (T/f) In quasi-static isothermal expansion of ideal gas 100% of heat supplied to the gas is converted intowork.
Definition
 True
Term
 Quasi-static Process
Definition
 Slow change where the system is always in thermodynamic equilibrium during the change. (The processes is reversible as shown on a PV-Diagram)
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