Class 8 Science — Chapter 4: Combustion and Flame
72 practice questions · 24 Easy · 24 Medium · 24 Hard
Practise Class 8 Science Chapter 4, "Combustion and Flame", with 72 NCERT-aligned multiple-choice questions. The set is split into 24 Easy, 24 Medium and 24 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams.
"Combustion and Flame" is one of the chapters where concept clarity across physics, chemistry and biology basics really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Combustion and Flame, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 8 Science mastery score. A few sample questions are shown below; sign in free to practise all 72.
Key concepts: Combustion and Flame (Class 8 Science)
This chapter covers combustion, the conditions and types of burning, the structure of a flame, and fuels with their efficiency.
- Combustion
- A chemical process in which a substance reacts with oxygen, giving out heat (and often light).
- Conditions for combustion
- A combustible substance, a supporter (oxygen), and reaching the ignition temperature.
- Types of combustion
- Rapid (e.g. burning gas), spontaneous (e.g. phosphorus) and explosive (e.g. firecrackers).
- Structure of a flame
- Three zones — the innermost (unburnt, dark), middle (yellow, partial combustion) and outermost (blue, complete combustion, hottest).
- Fuel efficiency
- Calorific value is the heat produced per kg of fuel; an ideal fuel is cheap, safe and burns cleanly.
Key formulas — Combustion and Flame
💡 Exam tips for Combustion and Flame
- The outermost (blue) zone of a flame is the hottest — complete combustion happens there.
- Fire is controlled by removing any one condition: fuel, oxygen, or heat (below ignition temperature).
Sample questions
Combustion is a chemical process in which a substance reacts with:
In combustion a substance reacts with oxygen to produce heat (and often light).
A burning candle covered with a glass tumbler soon goes out because:
The trapped oxygen gets used up, and without oxygen combustion cannot continue.
Assertion (A): A candle goes out when covered by a glass jar. Reason (R): Combustion needs a continuous supply of oxygen. Choose the correct option.
The jar cuts off oxygen; since combustion needs oxygen, the candle goes out — R explains A.
Combustion and Flame — FAQs
What are the key concepts in Class 8 Science Combustion and Flame?+
This chapter covers combustion, the conditions and types of burning, the structure of a flame, and fuels with their efficiency. Key ideas include Combustion, Conditions for combustion, Types of combustion, Structure of a flame, Fuel efficiency.
What does Class 8 Science Chapter 4 (Combustion and Flame) cover on XamBaaz?+
It covers 72 NCERT-aligned MCQs on "Combustion and Flame" — 24 Easy, 24 Medium and 24 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams.
Are these "Combustion and Flame" questions free to practise?+
Yes — sign in with Google to practise "Combustion and Flame" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Combustion and Flame" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
Practise all 72 questions free
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