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Heat. and Thermodynamics. Designed By Miyav. “ Heat from the sun is the driving force of life on earth”. “The science of Heat and is it’s relation to work is called thermodynamics ”. Electrical energy can produce or remove heat based on principles of “ Thermodynamics ”.
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Heat andThermodynamics Designed By Miyav
“Heat from the sun is the driving force of life on earth” Miyav
“The science of Heat andis it’s relation to work is called thermodynamics” Miyav
Electrical energy can produce or remove heat based on principles of “Thermodynamics” Miyav
Heat from burning coal produces steam, which runs Train locomotive coal, petrol, wood gives heat during burning (chemical reaction) Miyav
hot cold Miyav
summer winter Miyav
How much hot? How much cold? Measured by “temperature” Miyav
hot cold 15OC 45OC Miyav
What will be the temperature? Trichy Srinagar summer winter 40OC - 10OC Miyav
How much cold? How much hot? Measured by “temperature” Celsius- unit Thermometer 37OC 100OC 0OC Miyav
At -100 c Carbon dioxide gas becomes solid (it is called dry ice) At what temperature water becomes solid? Miyav
How much cold? How much hot? Measured by “temperature” Celsius or Kelvin 1000OC 5000OC -100OC Sun’s outer surface Gas freezes into solid Gold melts Miyav
Why ice cream is melting? Low temperature (ice cream) Solid Liquid Vapor (gas) High temperature Room temperature Miyav
How water becomes steam? Miyav
How water becomes steam? Low temperature Solid Phase change Liquid heating Vapor (air) High temperature Miyav
Heat transferred Heat flows from room air to ice cream to reach equilibrium. So ice cream melts why coffee becomes cold after some time? roomtemperature Heat flows from coffee to room air to reach equilibrium Miyav
Heat transferred roomtemperature Heat flow to reach thermal equilibrium Low High Miyav
Heat transfer mechanisms Conduction (occurs generally in solids) The heat is transferred along the body from one particle (molecule) to another without the movement of the particles themselves. This is called as conduction. Miyav
Metals are high conductivity material conductor (conductivity very high) Insulator (conductivity very less) Miyav
conductors insulators Wool metals Wood plastic Miyav
convection (occurs generally in fluids) The heat is transferred from hotter portions to colder portions by the actual movement of particles of a fluid is called convection. Miyav
Radiation (can occur without any medium) Thermal radiationis the energy radiated from hot surfaces as electromagnetic waves. It does not require medium for its propagation. Miyav
White colour tankers & white gaps Absorption of radiant heat by a body When radiant heat falls on a body a part of it is absorbed by it. There is an increase in its temperature due to this absorption. Miyav
If the surface of a body is painted black it absorbs more heat than when it is painted white. Black roof white roof Miyav
Why do we use petrol in aero planes instead of coal for running jet engines? Miyav
A train can run 1 Km 10 Kg of coal A train can run 4 Km 10 Kg of diesel It means that for same amount of mass, diesel produces larger heat compared to coal Miyav
We say that Diesel has high calorific content compared to coal Calorific value of a fuel is the total quantity of heat produced when a unit mass (or volume) of the fuel is burnt completely. Unit of calorific value is kJ/g Miyav
(KJ/g) High calorific zero ash LPG (100) petrol (50) diesel (45) coal (15) High ash wood (5) low calorific So in scooters, buses, we need to carry less amount of fuel, since the diesel’s calorific value is high Miyav
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