Terminologies for Revision

· Root Mean Square – average of the squares of the velocities of molecules of the gas

· Vapor Pressure – the vapor of a liquid formed at any temperature that exerts a pressure

· Saturated Vapor Pressure (SVP) – the pressure exerted by a vapor in a closed space at a given temperature is a maximum at that temperature

· Unsaturated Vapor Pressure – the pressure applied by a vapor in a closed space at a given temperature is less than its SVP at that temperature

· Surface Tension – tendency of the surface of a liquid to contract in area and thus behave like a stretched elastic membrane

· Capillary Effect – the rise of a liquid in a fine, hollow tube or in a narrow space

· Temperature – a measure of the kinetic energy of the molecules in a material

· Thermal Physics – is the study of the macroscopic effects of the microscopic molecules

· Molecular Kinetic Theory – analysis of matter in terms of atoms in continuous random motion

· Basic Postulates of Kinetic Theory:

o There are a large number of molecules moving in random directions with variety of speeds.

o The molecules are, on the average, far apart from one another.

o The molecules are assumed to obey the laws of classical mechanics and are assumed to interact with one another only when they collide.

o Collisions with another molecule or the wall of the container are assumed to be perfectly elastic.

· Boyle’s Law – states that the pressure of a fixed mass of gas is inversely proportional to its volume at constant temperature

· Charles’ Law – states that the volume of a fixed mass of gas at constant pressure is directly proportional to its absolute (Kelvin) temperature (this is the ENGLISH definition)

· Gay–Lussac’s Law – states that the pressure of a fixed mass of gas at constant volume is directly proportional to its absolute (Kelvin) temperature (this is the ENGLISH definition)

· Equation of State – pV = nRT (n = number of moles)

· Work Done – a macroscopic transfer of energy from the gas to the surroundings; W = PΔV

· Isobaric Process – a process in which the gas expands or contracts at constant pressure.

· Isochoric or Isovolumic Process – a process in which the volume of the gas stays fixed. Note that NO WORK is done on or by the gas in this process

· Isothermal Process – a process in which the temperature of the system remains constant

· Adiabatic Process – process during which the gas does not absorb or give out any thermal energy, so Q (heat) = 0

· Thermodynamics – macroscopic study of the behavior of systems; It was a mathematical theory developed before a detailed understanding of the particulate nature of gases

· Thermodynamic System – a macroscopic aspect of a problem than can be considered as a separate whole

· Thermodynamic Surroundings – everything in the problem outside the thermodynamic system

· Isolated System – no exchange of matter and heat

· Closed System – no exchange of matter but can exchange heat energy

· Open System – matter and heat can be exchanged

· Heat – an amount of thermal energy transferred from the surroundings to an ideal gas; It is a result of a temperature difference

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· Internal Energy – energy due to the intermolecular potential energy PE and kinetic energy KE of the molecules

· 1^st Law of Thermodynamics – states that when heat Q is added to a system while the system does work W, the internal energy U changes by an amount equal to Q – W; ΔU = Q – W

· State – defined as the physical condition of the system

· 2^nd Law of Thermodynamics – describes the directionality of natural thermodynamic processes

· 2^nd Law of Thermodynamics (Clausius’ Statement) – heat can flow spontaneously from a hot object to a cold object; heat will not flow spontaneously from a cold object to a hot object

· 2^nd Law of Thermodynamics (Engine Statement) – no cyclic process can convert heat completely into work

· 2^nd Law of Thermodynamics (Refrigerator Statement) – no cyclic process can transfer heat from a colder place to a hotter place with no input of mechanical work

· Heat Engine – any device that changes thermal energy into mechanical work

· Entropy – a quantitative measure of the degree of disorder or randomness of a system

· Irreversible Process – all thermodynamic processes that occur in nature; processes that proceed spontaneously in one direction but not the other

· Reversible Process – a process where the system is always in thermodynamic equilibrium; an idealization that can never be precisely attained in real world

· Efficiency of an engine – defined as the ratio of the work (W) it does to the heat input at the high temperature

· Carnot Engine – an idealized engine

· Efficiency of Carnot Engine – the heat Q₁ (or Q_H) and Q₂ (or Q_L) are proportional to the operating temperatures T₁ (T_H) and T₂ (T_L) in Kelvins

· Luminous Object – object that give off light

· Non-luminous object – object that do not give-off light

· Reflection – bouncing of light rays from a reflecting surface or mirror

· 1^st Law of Reflection – the incident ray, reflected ray and the normal to the reflecting surface all lie in the same plane

· 2^nd Law of Reflection – the angle of incidence is equal to the angle of reflection

· Regular Reflection – reflection that occurs in a smooth surface

· Irregular Reflection – reflection that occurs in a rough surface

· Virtual Image – an image formed by light rays that do not converge at the location of the image

· Real Image – an image formed by light rays that converge at the location of the image

· Concave Mirror – spherical mirror shaped like the inside of a bowl

· Convex Mirror – spherical mirror shaped like the outside of a bowl

· Principal Axis of a Spherical Mirror – a line that goes through the center of curvature to the center of the mirror

· Focal Length of a Spherical Mirror – distance from the principle focus to the center of the mirror; it is equal to one half of the radius of curvature of mirror

· Center of Curvature – the distance from the center of the mirror is equal to the radius of curvature of a mirror

· Object Distance – distance of the object (point 0) from the center of the mirror

· Image Distance – distance of the image (point I) from the center of the mirror

· Image Magnification – defined as the height of the image divided by the height of the object

· Index of Refraction – the ratio of the speed of light in vacuum (c) to the speed (v) in a given material medium

· Refraction – bending of light rays as it enters transparent material medium

· Snell’s Law – n₁sinα = n₂sinβ (α is angle of incidence and β is angle of refraction)

· Huygen’s Principle – all points in a given wave front are taken as point sources for the production of spherical secondary wavelets which propagate in space

· Lens – is a piece of clear plastic or glass with curved surfaces; it is usually circular, and its two faces are portion of a sphere

· Converging Lens – any lens that is thicker in the center than at the edges will make the parallel converge to a point

· Diverging Lens – lens that are thinner in the center than at the edges

· Principal Axis of a Lens – straight line passing through the center of the lens and perpendicular to its two surfaces

· Focal Point of a Lens - point where parallel rays meet after passing through the lens

· Focal Length of a Lens – distance of the focal point from the center of the lens

· Power of Lens – reciprocal of the focal length

· Diopter – unit for the power of lens

· Lens Aberration – distortion in an image; a distortion in an image produced by a lens or mirror, caused by limitations inherent to some degree in all optical systems

· Spherical Aberration – a distortion of an image caused by some light rays that pass through the edges of a lens focusing at a slightly different place from where light passing near the center of the lens focuses

· Chromatic Aberration – is a distortion of an image caused when light of different colors (and thus different speeds and refractions) focuses at different points when passing through a lens

Дата добавления: 2015-10-31