Flame


Combustion and Flame I - Concepts
Class - 8th Foundation NTSE 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

The blue zone in a LPG flame indicates __________________________.

                

Right Option : D
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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

Which of the following statements is/are correct?

1) The flame of a Bunsen burner is blue when the air hole is open and yellow when the air hole is closed.

2) The liquid or solid wax never catches fire.

3) A substance cannot catch fire if its temperature is higher than its ignition temperature.

4) Water should be poured over burning petrol,kerosene or diesel.

5) The middle zone of a candle emits the leaser light.

Right Option : A
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