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P net = σ e A ( T 2 4 − T 1 4 ) P net = σ e A ( T 2 4 − T 1 4 )
https://openstax.org/books/university-physics-volume-2/pages/1-key-equations
absolute temperature scale : scale, such as Kelvin, with a zero point that is absolute zero
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absolute zero : temperature at which the average kinetic energy of molecules is zero
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calorie (cal) : energy needed to change the temperature of 1.00 g of water by1.00°C1.00°C
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calorimeter : container that prevents heat transfer in or out
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calorimetry : study of heat transfer inside a container impervious to heat
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Celsius scale : temperature scale in which the freezing point of water is0°C0°Cand the boiling point of water is100°C100°C
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coefficient of linear expansion : (αα) material property that gives the change in length, per unit length, per1-°C1-°Cchange in temperature; a constant used in the calculation of linear expansion; the coefficient of linear expansion depends to some degree on the temperature of the material
https://openstax.org/books/university-physics-volume-2/pages/1-key-terms
coefficient of volume expansion : (ββ) similar toααbut gives the change in volume, per unit volume, per1-°C1-°Cchange in temperature
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conduction : heat transfer through stationary matter by physical contact
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convection : heat transfer by the macroscopic movement of fluid
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critical point : for a given substance, the combination of temperature and pressure above which the liquid and gas phases are indistinguishable
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critical pressure : pressure at the critical point
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critical temperature : temperature at the critical point
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degree Celsius : (°C°C) unit on the Celsius temperature scale
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degree Fahrenheit : (°F°F) unit on the Fahrenheit temperature scale
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emissivity : measure of how well an object radiates
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Fahrenheit scale : temperature scale in which the freezing point of water is32°F32°Fand the boiling point of water is212°F212°F
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greenhouse effect : warming of the earth that is due to gases such as carbon dioxide and methane that absorb infrared radiation from Earth’s surface and reradiate it in all directions, thus sending some of it back toward Earth
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heat : energy transferred solely due to a temperature difference
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heat of fusion : energy per unit mass required to change a substance from the solid phase to the liquid phase, or released when the substance changes from liquid to solid
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heat of sublimation : energy per unit mass required to change a substance from the solid phase to the vapor phase
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heat of vaporization : energy per unit mass required to change a substance from the liquid phase to the vapor phase
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heat transfer : movement of energy from one place or material to another as a result of a difference in temperature
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Kelvin scale (K) : temperature scale in which 0 K is the lowest possible temperature, representing absolute zero
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kilocalorie (kcal) : energy needed to change the temperature of 1.00 kg of water between14.5°C14.5°Cand15.5°C15.5°C
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latent heat coefficient : general term for the heats of fusion, vaporization, and sublimation
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mechanical equivalent of heat : work needed to produce the same effects as heat transfer
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net rate of heat transfer by radiation : Pnet=σeA(T24−T14)Pnet=σeA(T24−T14)
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phase diagram : graph of pressure vs. temperature of a particular substance, showing at which pressures and temperatures the phases of the substance occur
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radiation : energy transferred by electromagnetic waves directly as a result of a temperature difference
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rate of conductive heat transfer : rate of heat transfer from one material to another
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specific heat : amount of heat necessary to change the temperature of 1.00 kg of a substance by1.00°C1.00°C; also called “specific heat capacity”
https://openstax.org/books/university-physics-volume-2/pages/1-key-terms
Stefan-Boltzmann law of radiation : P=σAeT4,P=σAeT4,whereσ=5.67×10−8J/s·m2·K4σ=5.67×10−8J/s·m2·K4is the Stefan-Boltzmann constant,Ais the surface area of the object,Tis the absolute temperature, andeis the emissivity
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sublimation : phase change from solid to gas
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temperature : functionally defined as a quantity measured by a thermometer, which, at least for most of the systems discussed in this chapter, reflects the mechanical energy of particles in the system
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thermal conductivity : property of a material describing its ability to conduct heat
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thermal equilibrium : condition in which heat no longer flows between two objects that are in contact; the two objects have the same temperature
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thermal expansion : change in size or volume of an object with change in temperature
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thermal stress : stress caused by thermal expansion or contraction
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triple point : pressure and temperature at which a substance exists in equilibrium as a solid, liquid, and gas
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vapor : gas at a temperature below the critical temperature
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vapor pressure : pressure at which a gas coexists with its solid or liquid phase
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zeroth law of thermodynamics : law that states that if two objects are in thermal equilibrium, and a third object is in thermal equilibrium with one of those objects, it is also in thermal equilibrium with the other object
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Temperature is operationally defined as the quantity measured by a thermometer. It is proportional to the average kinetic energy of atoms and molecules in a system.
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Thermal equilibrium occurs when two bodies can freely exchange energy but no net energy is transferred between them.
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The zeroth law of thermodynamics states that when two systems,AandB,are in thermal equilibrium with each other, andBis in thermal equilibrium with a third systemC, thenAis also in thermal equilibrium withC.
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Three types of thermometers are alcohol, liquid crystal, and infrared radiation (pyrometer).
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The three main temperature scales are Celsius, Fahrenheit, and Kelvin. Temperatures can be converted from one scale to another using temperature conversion equations.
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The three phases of water (ice, liquid water, and water vapor) can coexist at a single pressure and temperature known as the triple point.
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Thermal expansion is the increase of the size (length, area, or volume) of a body due to a change in temperature, usually a rise. Thermal contraction is the decrease in size due to a change in temperature, usually a fall in temperature.
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Thermal stress is created when thermal expansion or contraction is constrained.
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Heat and work are the two distinct methods of energy transfer.
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Heat transfer to an object when its temperature changes is often approximated well byQ=mcΔT,Q=mcΔT,wheremis the object’s mass andcis the specific heat of the substance.
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Most substances have three distinct phases (under ordinary conditions on Earth), and they depend on temperature and pressure.
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Two phases coexist (i.e., they are in thermal equilibrium) at a set of pressures and temperatures.
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Phase changes occur at fixed temperatures for a given substance at a given pressure, and these temperatures are called boiling, freezing (or melting), and sublimation points.
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Heat is transferred by three different methods: conduction, convection, and radiation.
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Heat conduction is the transfer of heat between two objects in direct contact with each other.
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The rate of heat transferP(energy per unit time) is proportional to the temperature difference via conduction through a slab of material with ends in contact with two objects at different temperaturesThThandTcTcis proportional to the temperature differenceTh–TcTh–Tcand the contact areaA, and inversely proportional ...
https://openstax.org/books/university-physics-volume-2/pages/1-summary
Convection is heat transfer by the macroscopic movement of mass. Convection can be natural or forced, and generally transfers thermal energy faster than conduction.
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Radiation is heat transfer through the emission or absorption of electromagnetic waves.
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The rate of radiative heat transfer is proportional to the emissivitye. For a perfect blackbody,e=1e=1, whereas a perfectly white, clear, or reflective body hase=0e=0, with real objects having values ofebetween 1 and 0.
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The rate of heat emission depends on the surface area and the fourth power of the absolute temperature:P=σeAT4,P=σeAT4,whereσ=5.67×10−8J/s·m2·K4σ=5.67×10−8J/s·m2·K4is the Stefan-Boltzmann constant andeis the emissivity of the body. The net rate of heat transfer from an object by radiation isQnett=σeA(T24...
https://openstax.org/books/university-physics-volume-2/pages/1-summary
p V = N k B T p V = N k B T
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p 1 V 1 T 1 = p 2 V 2 T 2 p 1 V 1 T 1 = p 2 V 2 T 2
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p V = n R T p V = n R T
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[ p + a ( n V ) 2 ] ( V − n b ) = n R T [ p + a ( n V ) 2 ] ( V − n b ) = n R T
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p V = ​ 1 3 N m v 2 – p V = ​ 1 3 N m v 2 –
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v rms = 3 R T M = 3 k B T m v rms = 3 R T M = 3 k B T m
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λ = V 4 2 π r 2 N = k B T 4 2 π r 2 p λ = V 4 2 π r 2 N = k B T 4 2 π r 2 p
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τ = k B T 4 2 π r 2 p v rms τ = k B T 4 2 π r 2 p v rms
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K – = 3 2 k B T K – = 3 2 k B T
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E int = 3 2 N k B T . E int = 3 2 N k B T .
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Q = n C V Δ T Q = n C V Δ T
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C V = d 2 R C V = d 2 R
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f ( v ) = 4 π ( m 2 k B T ) 3 / 2 v 2 e − m v 2 / 2 k B T f ( v ) = 4 π ( m 2 k B T ) 3 / 2 v 2 e − m v 2 / 2 k B T
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v ¯ = 8 π k B T m = 8 π R T M v ¯ = 8 π k B T m = 8 π R T M
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v p = 2 k B T m = 2 R T M v p = 2 k B T m = 2 R T M
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Avogadro’s number : NA,NA,the number of molecules in one mole of a substance;NA=6.02×1023NA=6.02×1023particles/mole
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Boltzmann constant : kB,kB,a physical constant that relates energy to temperature and appears in the ideal gas law;kB=1.38×10−23J/KkB=1.38×10−23J/K
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critical temperature : TcTcat which the isotherm has a point with zero slope
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Dalton’s law of partial pressures : physical law that states that the total pressure of a gas is the sum of partial pressures of the component gases
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degree of freedom : independent kind of motion possessing energy, such as the kinetic energy of motion in one of the three orthogonal spatial directions
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equipartition theorem : theorem that the energy of a classical thermodynamic system is shared equally among its degrees of freedom
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ideal gas : gas at the limit of low density and high temperature
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ideal gas law : physical law that relates the pressure and volume of a gas, far from liquefaction, to the number of gas molecules or number of moles of gas and the temperature of the gas
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internal energy : sum of the mechanical energies of all of the molecules in it
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kinetic theory of gases : theory that derives the macroscopic properties of gases from the motion of the molecules they consist of
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Maxwell-Boltzmann distribution : function that can be integrated to give the probability of finding ideal gas molecules with speeds in the range between the limits of integration
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mean free path : average distance between collisions of a particle
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mean free time : average time between collisions of a particle
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mole : quantity of a substance whose mass (in grams) is equal to its molecular mass
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most probable speed : speed near which the speeds of most molecules are found, the peak of the speed distribution function
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partial pressure : pressure a gas would create if it occupied the total volume of space available
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peak speed : same as “most probable speed”
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pVdiagram : graph of pressure vs. volume
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root-mean-square (rms) speed : square root of the average of the square (of a quantity)
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supercritical : condition of a fluid being at such a high temperature and pressure that the liquid phase cannot exist
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universal gas constant : R, the constant that appears in the ideal gas law expressed in terms of moles, given byR=NAkBR=NAkB
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