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Heat
1. In physics and chemistry, heat is energy transferred from one body to another by thermal interactions. The transfer of energy can occur in a variety of ways, among them conduction,radiation, and convection.
The SI unit of heat is the joule. Heat can be measured by calorimeter, or determined indirectly by calculations based on other quantities, relying for instance on the first law of thermodynamics. In calorimeter, the concepts of latent heat and of sensible heat are used. Latent heat produces changes of state without temperature change, while sensible heat produces temperature change heat, energy that is transferred from one body to another as the result of a difference in temperature. If two bodies at different temperatures are brought together, energy is transferred—i.e., heat flows—from the hotter body to the colder. The effect of this transfer of energy usually, but not always, is an increase in the temperature of the colder body and a decrease in the temperature of the hotter body.
Units of Heat Energy
Heat being a form of energy can be measured. What is the unit of heat energy?
In CGS system, heat is measured in calories. Calorie is defined as 'the heat energy required to increase the temperature of 1gm of water through one degree Celsius'.
In SI system, heat energy is measured in joules (J). Infact, in SI system all forms of energy is measured in joules.
One calorie = 4.185 joules.
A larger unit called Kilocalorie is also in use. 1 kilocalorie = 1000 calories.
Energy contents of food is usually measured in kilocalories. The calories counted in food are actually kilocalories. For example, the energy value of 100 g of baked potato is equal to 100 calories or 100 kilocalories. 2. Sources of heat * The Sun
The sun is a part of our solar system. Thus, it is a natural source of heat energy. Sunlight is important for the existence of all living organisms on the planet. This form of heat energy is also called solar energy.
Sun is a natural

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