Multiple choice

Which of the following is not a zone of flame?

  1. Dark zone

  2. Luminous zone

  3. Combustible zone

  4. Non luminous zone
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A candle flame has three zones: the dark zone (innermost, unburnt vapor), luminous zone (middle, partial combustion with glowing carbon particles), and non-luminous zone (outermost, complete combustion). 'Combustible zone' is not a standard term used to describe flame zones.

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