How many zones are present in a luminous Bunsen burner flame?

Explanation

The luminous bunsen burner flame has four zones namely:

• Dark zone/ zone of unburnt gas; burning of the gas does not take place here, it is dark and cool.
• Luminous yellow zone; the gas burns in this zone but not completely because of limited air. Tiny particles glow in this region to give out light.
• Thin outer zone; the zone is colorless and gas burns completely due to plenty of air.
• Blue zone; this zone receives plenty of air and burning is more complete than in the luminous zone.