Combustion and Flame
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Notes
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PYQ MCQs
20
Subjective Assessment · Science · Combustion and Flame
15 questions · 50 marks · write your answer (or on paper), then reveal the scoring key to self-assess.
Short Answer
5 questions × 2 marks- 12 marks
Define the ignition temperature of a substance.
- 22 marks
Give two examples each of combustible and non-combustible substances.
- 32 marks
Why do non-metals form acidic oxides on burning?
- 42 marks
What is smouldering? Give one example.
- 52 marks
State any two precautions to prevent fire caused by electrical faults.
Medium Answer
5 questions × 3 marks- 13 marks
Draw the three zones of a candle flame and label them.
- 23 marks
Explain why hydrogen is considered the cleanest fuel.
- 33 marks
What is spontaneous combustion? Give one example.
- 43 marks
Define the calorific value of a fuel and state its unit.
- 53 marks
Why is the outermost zone of a flame the hottest zone?
Long Answer
5 questions × 5 marks- 15 marks
With the help of a labelled diagram, describe the three zones of a candle flame. Explain the colour of each zone.
- 25 marks
Explain the process of combustion with an example. List the conditions required for combustion to take place.
- 35 marks
Why is petrol stored in closed containers? Discuss the role of oxygen and ignition temperature in your answer.
- 45 marks
A fire breaks out in a kitchen due to overheated oil in a pan. List the steps you would take to put it out and explain why water should not be used.
- 55 marks
Compare wood and LPG as fuels in terms of calorific value, pollution and availability. Which would you prefer and why?