# Heat and Conductivity - Physical Engineering - Lecture Slides, Slides for Engineering Physics

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These are the Lecture Slides of Physical Engineering which includes Gain of Heat, Loss of Heat, Adiabatic Expansion, Expense of Internal Energy, Kinetic Theory of Gases, Continuous Motion, Pumping Speed of System, Therma...
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Heat And Conductivity

What is heat? • Form of energy. • Associated with the motion of atoms or molecules. • The more motion, the more heat is generated. • Heat can be measured by an instrument called

calorimeter at constant temperature. • The movement of heat from a warmer object to a

colder one .

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HEAT AND CONDUCTIVITY

Specific Heat • The ability of a substance to absorb heat energy

(specific heat) . • Different substances absorb heat at different rates. • The greater the mass of the object the more heat is

absorbed.

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HEAT AND CONDUCTIVITY

Forms of heat transfer Three forms of heat transfer: • Conduction • Convection • Radiation

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HEAT AND CONDUCTIVITY

Conduction • Conduction involves the

transfer of heat through direct contact

• Heat conductors conduct heat well, insulators do not

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HEAT AND CONDUCTIVITY

Convection • Takes place in liquids

and gases as molecules move in currents.

• Heat rises and cold settles to the bottom.

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HEAT AND CONDUCTIVITY

through space. • Energy from the sun

being transferred to the Earth.

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HEAT AND CONDUCTIVITY

• Warm air mass bringing a change in the weather. • Wire getting hot from an electric appliance. Temperature and Heat. • Kinetic energy is the energy of motion. • Temperature is the measure of the average kinetic energy

of an object.

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HEAT AND CONDUCTIVITY

• Measuring Heat • Increase in temperature • Addition of heat • A decrease in temperature • Removal of heat

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HEAT AND CONDUCTIVITY

Calories • Unit for measuring heat. • The amount of heat needed to raise 1 gram of water

one degree Celsius. Joule • Joule is another unit for measuring heat. • Mass and type of substance determine the amount of

temperature change.

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HEAT AND CONDUCTIVITY

What is a calorimeter? • Device used to measure the heat given off during

chemical reactions Forms Of Heat • Heat and Phase Changes • A phase change is a physical change that requires a

change in heat energy • Addition or removal of heat

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HEAT AND CONDUCTIVITY

Effect Of Heat • Heat expansion • The expansion of a substance due to heat • Most solids, liquids, and gases expand as they are

heated Expansion of water • Between 4ºC and 0ºC, water EXPANDS as it cools

and turns into a solid

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HEAT AND CONDUCTIVITY

Thermostat • A thermostat is a device that controls the temperature. • The switch of a thermostat is a bimetallic strip. Bimetallic Strip • Two different metals that are bound together. • They expand at different rates when heated. • Used as a switch in a thermostat.

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HEAT AND CONDUCTIVITY

Conductivity • Conductivity is the measure of the ease at which an

electric charge or heat can pass through a material. • A conductor is a material which gives very little

resistance to the flow of an electric current or thermal energy.

• Materials are classified as metals, semiconductors, and insulators. Metals are the most conductive and insulators (ceramics, wood, plastics) the least conductive.

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