NCERT Important Questions Class 8 Science chapter 4 with Answer solution with pdf. Here We Provides Class 1 to 12 all Subjects NCERT Solution with Notes, Question Answer, CBSE and HBSE Important Questions, MCQ and old Question Papers for Students.
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CBSE and HBSE Solution of Class 8 Science chapter 4 Combustion and Flame important Questions And Answer solution.
Class 8 Science Chapter 4 Important Questions and Answer
Q.1 What is Combustion?
Ans – A chemical process in which a substance reacts with oxygen to give off heat is called combustion.
Q.2 What is Fuel?
Ans – The Substance that undergoes combustion is known as fuel.
Q.3 What is Ignition Temperature?
Ans – The lowest temperature at which any substance catches fire is called its ignition temperature.
Q.4 What is Inflammable Substance?
Ans – The Substance that has very low ignition temperature and can easily catch fire with a flame is called inflammable substance.
Q.5 How many types of Combustion occurs?
Ans – There is mainly three types of combustion.
- Rapid Combustion
- Spontaneous combustion
- Explosion
Q.6 Describe the Structure of Candle flame. OR What are the Different Zones of Candle? ( Most Important )
Ans – There are the following parts of a Candle Flame. Let’s Discuss one by one.
- Outer Zone – This is the hottest part of candle flame looks in blue colour.
- Middle Zone- This is a moderate hot part of a candle flame look in yellow colour.
- Innermost Zone– This part is the least hot part of a candle flame. It has black in colour due to carbon vapours.
Q.7 What is acid rain? ( Most Important )
Ans – Oxides of Sulphur and nitrogen dissolve in rain water and forms acid. This acid falls on the earth surface as acid rain.
Q.8 What is Fuel Efficiency?
Ans – The total amount of energy produced by one Kilogram of Fuel is known as fuel Efficiency. Unit of Fuel Efficiency is KJ / Kg.
Q.9 How carbon dioxide is able to stop fires? ( Most Important )
Ans – Carbon Dioxide is Heavy gas than oxygen so it makes a layer around substance and cuts off the supply of oxygen. Without oxygen fire is Impossible.
Q.10 Which Zone of the flame is used by Goldsmith for melting gold and silver?
Ans – Outermost Zone of Flame is used by goldsmith because the blue coloured outer zone is the hottest part of the flame. With this high-temperature gold and silver can be easily melted.