Flame


Combustion and Flame I - Concepts
Class - 8th ISO Subjects
 
 
Concept Explanation
 

Flame

A flame is a region where combustion of fuel takes place.

Substances which vapourise during burning produce flames. E.g. kerosene, wax etc. Substances which do not vapourise during burning do not produce flames. E.g. coal, charcoal etc. The colour of flame depends on: Temperature, amount of air available, nature of the substance burning.

      Luminous Flame

        Non Luminous Flame

  1. Give yellow flame

      1.  Give blue color flame

   2. Emits lot of light

     2.  Emit very little light

   3. Observed when there is insufficient oxygen

      or incomplete combustion

      3. Observed when there is sufficient amount 

       oxygen available

   4. Temperature is less and leaves behind black  soot and other residue.

    4. Leave no residues behind

Sample Questions
(More Questions for each concept available in Login)
Question : 1

Why are the spint and kesosene lamps made in such a way that the free end of the wicks with the flamer remains totally cut off from the fuel?

  • A: The fuel vaporises at room temperature.
  • B: The fuel is highly inflammable.
  • C: The calorific value of fuel can be increasesd.
Right Option : A
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Explanation
Question : 2

An electric spark is struck between two electrodes placed near each other, inside a closed tank full of petrol. What wiII happen ?                 

Right Option : D
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Explanation
Question : 3

Total amount of heat produced by a fuel having calorific value of 20 kJ/kg was found to be 50,000 Joules. How much fuel was burnt ?

                     

                     

Right Option : D
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