DONE BY

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DONE BY-

• SPRADHA GAUTAM
• 11th SCIENCE

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PHYSICS PROJECT WORK

• THERMODYNAMICS

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TOPICS/CONTENTS

• INTRODUCTION
• THERMAL EQUILIBRIUM
• ZEROTH LAW OF THERMODYNAMICS
• WORK,HEAT,INTERNAL ENERGY

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Introduction

• Thermodynamics, field of physics that describes
  and correlates the physical properties of
  macroscopic systems of matter and energy. The
  principles of thermodynamics are of fundamental
  importance to all branches of science and
  engineering.
• A central concept of thermodynamics is that of
  the macroscopic system, defined as a
  geometrically isolable piece of matter in
  coexistence with an infinite, unperturbable
  environment.

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• The state of a macroscopic system in equilibrium
  can be described in terms of such measurable
  properties as temperature, pressure, and volume,
  which are known as thermodynamic variables. Many
  other variables (such as density, specific heat,
  compressibility, and the coefficient of thermal
  expansion) can be identified and correlated, to
  produce a more complete description of an object
  and its relationship to its environment.

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• When a macroscopic system moves from one state of
  equilibrium to another, a thermodynamic process
  is said to take place. Some processes are
  reversible and others are irreversible. The laws
  of thermodynamics, discovered in the 19th century
  through painstaking experimentation, govern the
  nature of all thermodynamic processes and place
  limits on them.

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Zeroth law of thermodynamics

• The vocabulary of empirical sciences is often
  borrowed from daily language. Thus, although the
  term temperature appeals to common sense, its
  meaning suffers from the imprecision of
  nonmathematical language. A precise, though
  empirical, definition of temperature is provided
  by the so-called zeroth law of thermodynamics as
  explained below.

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• When two systems are in equilibrium, they share a
  certain property. This property can be measured
  and a definite numerical value ascribed to it. A
  consequence of this fact is the zeroth law of
  thermodynamics, which states that when each of
  two systems is in equilibrium with a third, the
  first two systems must be in equilibrium with
  each other. This shared property of equilibrium
  is the temperature

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• If any such system is placed in contact with an
  infinite environment that exists at some certain
  temperature, the system will eventually come into
  equilibrium with the environmentthat is, reach
  the same temperature. (The so-called infinite
  environment is a mathematical abstraction called
  a thermal reservoir in reality the environment
  need only be large relative to the system being
  studied.)

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• Temperatures are measured with devices called
  thermometers (see Thermometer). A thermometer
  contains a substance with conveniently
  identifiable and reproducible states, such as the
  normal boiling and freezing points of pure water.
  If a graduated scale is marked between two such
  states, the temperature of any system can be
  determined by having that system brought into
  thermal contact with the thermometer, provided
  that the system is large relative to the
  thermometer.

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Thermal equilibrium

• Thermal equilibrium is when a system's
  macroscopic thermal observables have ceased to
  change with time. For example, an ideal gas whose
  distribution function has stabilised to a
  specific Maxwell- Boltzmann distribution would be
  in thermal equilibrium. This outcome allows a
  single temperature and pressure to be attributed
  to the whole system. Thermal equilibrium of a
  system does not imply absolute uniformity within
  a system for example, a river system can be in
  thermal equilibrium when the macroscopic
  temperature distribution is stable and not
  changing in time, even though the spatial
  temperature distribution reflects thermal
  pollution inputs and thermal dispersion.

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WORK - W, HEAT - Q, and INTERNAL ENERGY - U

• WORK WUseful Energy Transfered across the
  System's Boundaries, capable of producing
  Macroscopic-Mechanical Motion of a the system's
  Center-of-Mass.
• W Work done by (or on) one system on another
  system
• ENERGY FLOW
• OUTW gt 0System Does External WorkSys --gt Work
  INTOW lt 0Work Done on the SystemWork --gt Sys

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• HEAT QEnergy Transfer across the System's
  Boundaries that cannot produce Macroscopic-Mechani
  cal Motion of the system's Center-of-Mass. Energy
  Transfer at the Molecular Level .
• Q Microscopic Energy flow into (or out of) the
  System
• ENERGY FLOW
• INTOQ gt 0System Absorbs HeatHeat --gt Sys OUTQ lt
  0 System Releases HeatSys --gt Heat

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• INTERNAL ENERGY UEnergy Stored in a System at
  the Molecular Level.The System's Thermal Energy
  -the Kinetic Energy of the atoms due to their
  random motion relative to the Center of Mass plus
  the binding energy (Potential Energy) that holds
  the atoms together.
• U Microscopic Energy contained in the System