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Author Archives: admin

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 examples

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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Conduction heat transfer definition and examples

What are three types of heat transfer? “when two bodies at different temperature are in thermal contact with each other,thermal energy from a hot body flows to a cold body in the form of heat.This is called heat transfer.” Transfer of heat is a natural process.It continues all the time as long as the bodies in thermal contact are at ...

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Heat thermal energy sources

What is heat energy? “Heat is a form of energy that flows between a system and its environment by virtue of a temperature difference between them.”Heat is therefore,called as the energy in transient.Once the heat enters a body,it becomes its internal energy and no longer exists as heat energy. It is a common observation that if you place a hot ...

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Temperature Conversion scales formulas examples

What are different scales of temperature? There are three different scales of temperature,which are given in the list: Celsius scale Fahrenheit scale Kelvin scale   1.Temperature Conversion from Celsius to Kelvin scale: The temperature T on kelvin scale can be obtained by adding 273 in the temperature C on Celsius scale.Thus the formula to convert Celsius to kelvin is given ...

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How does a thermometer work?

“Thermometer is the device which is used to measure the temperature of a body.”Some substances have property that changes with temperature.Substances that show a change with temperature can be used as a thermometric material.For example,some substances expand on heating,some change their colors,some change their electric resistance ,etc.Nearly all the the substances expand on heating.Liquids also expand on heating and are ...

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Temperature scales with examples

What is temperature? “The temperature of a body is the degree of hotness or coldness of the body.”or “Average kinetic energy of atoms or molecules.”When we touch a body,we feel it hot or cold.The temperature of a body tells us how hot or cold a body is. When two systems are in thermal equilibrium,we say that they have the same ...

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Standard resistor values

Carbon resistors are most common in electronic equipment.They consists of a high grade ceramic rod or cone ( called the substrate on which is deposited a thin resistive film of carbon. The numerical value of their resistance is indicated by a colour code which consists of bands of different colors printed on the body of the resistor.The color used in ...

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Describe the structure of an atom

what is Atom? “Atom is the smallest particle of an element that possesses the unique characteristics of that element.”All matter is composed of atoms;all atoms consists of electrons,protons, and neutrons except normal hydrogen,which does not have a neutron.Each element in the periodic table has a unique atomic structure,and all atoms within a given element have the same number of protons.At ...

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