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Thermodynamics

Efficiency of Carnot engine

Carnot Engine: Sadi Carnot in 1840 described an ideal engine using only isothermal and adiabatic processes.The carnot engine is free from friction and heat loses. Sadi showed that a heat engine operating in an ideal reversible cycle between two heat reservoirs at different temperatures would be the most efficient. Construction of carnot engine: It consists of following parts: A cylinder ...

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Intermolecular forces examples

What are intermolecular forces? Forces between molecules are of electromagnetic origin.All molecules contain electric charges in motion.These molecules are electrically neutral in the sense that the negative charge of the electron is equal and opposite charge to the positive charge of the nuclei.This does no mean,however that the molecules do not interact electrically.For example when two  molecules approach each other ...

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Specific Heat capacity formula

Specific Heat Capacity: Specific heat of a substance is the amount of heat required as raise the temperature of 1 kg mass of that substance through 1 K. Generally, when a body is heated, its temperature increases. Increase in the temperature of a body is found to be proportional to the amount of heat absorbed by it. It has also ...

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thermal Expansion coefficients of metals

Thermal expansion: Most of the substances solids, liquid and gases expand on heating and contract on cooling. Their thermal expansions and contractions are usually small and are not noticeable. However, these expansions and contractions are important in our daily life. The kinetic energy of the molecules of an object depends on its temperature. The molecules of a solid vibrate with ...

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First and second Law of thermodynamics

First law of thermodynamics: When heat is added to a system there is an increase in the internal energy due to the rise in temperature,an increase in pressure or change in the state.If at the same time,a substance is allowed to do work on its environment by expansion,the heat Q required will be the heat necessary to change the internal ...

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First Law of Thermodynamics

In any thermodynamic process, when heat Q is added to a system, this energy appears as an increase in the internal energy ΔU stored in the system plus the work W done by the system on its surroundings. when heat is added to a system there is an increase in the internal energy due to the rise in temperature, an increase ...

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Internal energy

what is internal energy? “The sum of all forms of molecular energies (kinetic and potential ) of a substance is termed as its internal energy.”In the study of thermodynamics,usually ideal gas is considered as a working substance. the molecules of an ideal gas are mere mass points which exert no force on one another. so the internal energy of an ...

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Evaporation and condensation

“Evaporation is the changing of a liquid into vapours (gaseous state) from the surface of the liquid without heating it.” Take some water in a dish.The water in the dish will disappear after some time.It is because the the molecules of water are in constant motion and possess kinetic energy.Fast moving molecules escape out from the surface of water and ...

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Radiation heat transfer

What is radiation? “Radiation is the mode of transfer of heat from one place to another in the form of waves called electromagnetic waves.” Our sun is the major source of heat energy.But how does this heat energy reach the earth?It reaches us neither by conduction nor by convection,because the space between the sun and the Earth’s atmosphere is empty.There ...

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Convection heat transfer

What is convection? “Transfer of heat by actual movement of molecules from hot place to a cold place is known as convection.” Liquids and gases are poor conductors of heat.However,heat is transfer through  fluids(liquids or gases)easily by another method called convection. Why a balloon inflated with hot shown in figure .rise up?a liquid or a gas becomes lighter (less dense) ...

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