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How does fire brigade work to extinguish fire ?


When fire brigade arrives, it pours water on the fire. Water cools the combustible material, so that its temperature is brought below its ignition temperature. They cut-off electricity and remove the combustible material from surrounding. This prevents the fire from spreading. Water vapour also surrounds the combustible material, helping in the cutting off the supply of air. So the fire is extinguished.


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Why does wood not burn with a burning matchstick ?


Wood does not burn with a burning matchstick because the ignition temperature of the wood is high and matchstick burns out soon. It needs to he heated for a longer period so, it does not burn with burning matchstick.

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Why is water poured on wood to extinguish burning wood ?


Water is poured on burning wood to extinguish fire because water absorbs large amount of heat and the temperature of wood falls below its ignition temperature and fire is blown out.


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Why does an empty paper glass catch fire easily but one having water in it does not burn ?


The empty glass catches fire easily, but the glass with water does not because when heated the heat produced is absorbed by the water. Thus, its temperature is lowered and it does not catch fire.

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Why is the colour of outer zone of a candle flame is blue while middle zone is yellow coloured ?


Outermost Zone : It is blue coloured because complete combustion takes place in this part due to sufficient amount of oxygen. It is the hottest part of the flame.

Middle Zone : The colour of the middle zone is yellow because incomplete combustion takes place in this part with the lack of oxygen. It is less hot part than outer part of the flame.

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