Extra questions - Combustion and flame - Class 8

Class 8 Science - Combustion and Flame - Extra questions

10. Charcoal does not produce flame on burning. Why?

• It does not vapourise for producing flame
• It never burns so do not produce flame
• It changes in to liquid state while burning so do not produce flame
• It vapourises and burns vigorously.

9. ___________ is present in the __________ zone of a candle flame. 

• Complete combustion, luminous zone
• Incomplete combustion, non luminous zone
• Complete combustion, non luminous zone
• Complete combustion, dark

8. The flame of a L.P.G stove is _______ in color _________________. 

• Yellow, due to incomplete combustion of L.P.G.
• Blue, due to presence of carbon particles.
• Colorless, due to presence of dust particles
• Blue, due to complete combustion of L.P.G.

7. Partial combustion takes place in the _____ of a candle flame. 

• Luminous zone
• Non-luminous zone
• Combustible zone
• Dark zone

6. The color of the middle zone of a candle flame is ___________. 

• Black
• Blue
• Bluish red
• Yellow

5. The _____ zone of the candle flame is ________ hot. 

• Outermost, least
• Innermost, most
• middle, most
• Innermost, least

4. The innermost region of a candle flame is ____ in color ____________. 

• Black, due to complete combustion of wax
• Blue, due to complete combustion of wax.
• Black, due to the presence of unburnt wax vapours.
• Yellow, due to the presence of unburnt wax vapours.

3. Goldsmiths use the outermost zone of a flame with a metallic blowpipe for melting gold and silver. Why?

• It has vapors that will help in melting gold and silver
• Oxygen supply is less in this zone
• It has unburnt carbon particles
• It is the hottest zone

2. The outermost zone of a candle's fame is _______ in color. Why?

• Blue, due to less supply of oxygen.
• Blue, due  to a sufficient supply of oxygen
• Yellow,  due to the presence of carbon particles
• Yellow, due to a sufficient supply of oxygen

1. Which is the ODD ONE OUT when it comes to zones of flame?

• Dark zone
• Combustible zone
• Luminous zone
• Non-luminous zone

COMBUSTION AND FLAME - PDF WORKSHEET - HOTS QUESTIONS

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COMBUSTION AND FLAME - ONLINE TEST

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COMBUSTION AND FLAME - HOT QUESTIONS