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Heat (Saanjali) - Coggle Diagram

- - - - Heat is transmitted through a medium
        
        Vibration of particles
        
        This is a slow process of heat transfer
        
        Motion of free electrons
        
        This is a fast process of heat transfer
  - - - Heat is transferred from one region of a fluid to another in a circulatory manner called a convection current.
        
        A convection current is set up due to a change in the density of the fluid
  - - - heat transfer does not require a medium, so it can take place in vacuum
        
        All objects can emit infrared radiation. Heat energy from infrared radiation is called the radiant heat.
        
        All objects can either absorb or emit radiant heat. When an object absorbs radiant heat, its temperature increases. However, when an object emits radiant heat, its temperature decreases.
        
        The rate of heat transfer by radiation is affected by three factors
        
        Surface area of an object
        
        If an object has a larger surface area, the rate of heat transfer by radiation is faster.
        
        Surface temperature of an object
        
        If the surface of an object has a higher temperature, it will radiate heat at a higher rate.
        
        Colour and texture of an object.
        
        Black, dull and rough surfaces are the best absorbers and emitters of radiant heat. Hence, they are the poor reflectors of heat. White, shiny and smooth surfaces are the poor absorbers and emitters of heat. Hence, they are the good reflectors of heat.
- - - - Substances in the same physical state have different rates of expansion and contraction too.
- - - - When heat enters an object, one of two things can take place
        
        The temperature of the object increases
        
        The object changes in size or physical state.