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In which of the following situations, water cannot be used to extinguish fires? (A) electrical fire (B) burning of wood (C) burning of petrol (D) burning of paper

In which of the following situations, water cannot be used to extinguish fires? (A) electrical fire (B) burning of wood (C) burning of petrol (D) burning of paper Correct Answer A and C

Concept :

Extinguishing fire :

  • When there is any fire breakout water is poured on the fire.
  • Water cools the combustible material so that its temperature is brought below its ignition temperature.
  • This prevents the fire from spreading.
  • Water vapours also surround the combustible material, helping in cutting off the supply of air
  • Hence the fire is extinguished.

Explanation :

  • The most common fire extinguisher is water.
  • But water works only when things like wood and paper are on fire.
  • If electrical equipment is on fire, water may conduct electricity and harm those trying to douse the fire.
  • Water is also not suitable for fires involving oil and petrol.
  • As water, sinks below the oil, it keeps burning on the top.
  • For fires involving electrical equipment and inflammable materials like petrol, carbon dioxide (CO2 ) is the best extinguisher.

the correct answer is electrical fire and the burning of petrol.

Important Points

  • CO2, being heavier than oxygen, covers the fire like a blanket.
  • Since the contact between the fuel and oxygen is cut off, the fire is controlled. 

 Key Points

  • There are three essential requirements for producing fire.
  • These are fuel, air (to supply oxygen), and heat (to raise the temperature of the fuel beyond the ignition temperature).
  • The fire extinguisher is to cut off the supply of air and bring down the temperature of the fuel. 

Related Questions

In which of the following situations, water cannot be used to extinguish the fire? a) burning of wood b) burning of diesel c) burning of paper d) short-circuit of electrical appliance
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