Question 1: Which of these is a combustible substance?
Answer: (b) Paper
Question 2: Which of the following is non-combustible substance?
Answer: (c) Iron
Question 3: Which of the following is an inflammatory substance?
Answer: (b) Alcohol
Question 4: A flame has how many zones?
Answer: (c) Three
Question 5: The outermost zone of flame is of which colour?
Answer: (a) Blue
Question 6: The middle zone of flame is of which colour?
Answer: (b) Orange
Question 7: Which is the best fuel for kitchen; in present times?
Answer: (a) LPG
Question 8: Which part of flame is used by goldsmith?
Answer: (a) Blue
Question 9: Which of the following does not produce flame while burning?
Answer: (d) Coal
Very Short Answer Type Questions
Question 1: Define combustion?
Answer: Combustion is a chemical process in which a substance reacts with oxygen to give off heat.
Question 2: What is combustible substance?
Answer: A substance which can undergo combustion is called a combustible substance.
Question 3: What is a non-combustible substance?
Answer: A substance which cannot undergo combustion is called a non-combustible substance.
Question 4: What is ignition temperature?
Answer: Ignition temperature is the minimum temperature at which combustion starts in a substance.
Question 5: What is an inflammable substance?
Answer: A substance which has very low ignition temperature so that is can easily catch fire is called an inflammable substance, e.g. petrol, alcohol, etc.
Question 6: What is a fire extinguisher?
Answer: The substance which is used for putting off fire is called fire extinguisher.
Question 7: What is rapid combustion?
Answer: When combustion happens at a faster rate, it is called rapid combustion.
Question 8: Define calorific value of a fuel.
Answer: The amount of heat energy produced on combustion of 1 kg of a fuel is called calorific value of that fuel. It is expressed as kilo Joule per kg (kJ/kg).
Question 9: What is spontaneous combustion?
Answer: When combustion starts on its own; without an apparent cause; it is called spontaneous combustion.