Class 8 Science Chapter 6 MCQ (Multiple Choice Questions) of Combustion and Flame. After doing NCERT Books, these questions help in revising the chapter for tests and exams. There are more than 80 questions divided into sets of 10 questions each. These questions cover all the important topic and intext questions from NCERT Books. Some exercises questions are also included in these practice tests.
Class 8 Science Chapter 6 MCQ Online Tests for 2022-2023
| Class: 8 | Science |
| Chapter 6: | Combustion and Flame |
| Contents: | MCQ Online Tests with Explanation |
Class 8 Science Chapter 6 MCQ with Answers and Explanation
MCQ Online tests for class 8 Science chapter 6 are given below with answer and explanation. All the questions are taken from Latest CBSE NCERT Books for 2022-2023 and are important for examination point of view. These MCQ Quiz questions takes hardly 30 minutes to complete and help to score better than ever.
Q1
In which of the following sentences are incorrect?
[A]. A chemical process in which a substance reacts with oxygen to give off heat, is called combustion.
[B]. When the clothes of a person catch fire, the person is covered with the blanket to extinguish fire.
[C]. The lowest temperature at which a substance catches fire is called, its ignition temperature.
[D]. The substances which give very high ignition, temperature and can easily catch fire with a flame, are called inflammable substances.
Q2
Consider the following statements, choose the incorrect one:
[A]. Some substances on combustion produces heat and flame.
[B]. The amount of heat energy produced on complete combustion of 1 kg of fuel is called its calorific value.
[C]. When CNG burns, it produces harmful products in very small amount.
[D]. None of the above.
Q3
Choose the incorrect statement from the following: “A good fuel is one which …
[A]. Is readily available
[B]. Produces a large amount of heat
[C]. Leaves behind many and desirable substances
[D]. Burns easily in air at a moderate rate
Q4
Boojho is writing some statements, choose the correct statement and help him:
[A]. Calorific value of wood is higher than that of coal.
[B]. Magnesium is a non-combustible metal.
[C]. Air is necessary for combustion.
[D]. All the above.
Q5
Which one among the following is considered as the cleanest fuel?
[A]. Cow dung cake
[B]. Petrol
[C]. Kerosene
[D]. Hydrogen gas
Q6
Consider the following statements and choose the correct one:
[A]. The substance which have very low ignition temperature and can easily catch fire with a flame are called inflammable substance.
[B]. The amount of heat energy produced on complete combustion of 1 kg of a fuel is called its calorific value.
[C]. Inflammable substance have very low ignition temperature.
[D]. All the above
Q7
In villages, people use wood as fuel because:
[A]. It is considered to be an ideal fuel
[B]. Of its easily available and low cost
[C]. It is environment friendly
[D]. It catches fire easily
Q8
Boojho appeared in class test where he wrote some statements but he confused to know the incorrect statement. Would you help him to know that?
[A]. Greater the calorific value, better is the fuel.
[B]. Middle zone is the hottest zone of a flame.
[C]. The substances which vaporize during burning give flame.
[D]. Calorific value of wood is higher than that of coal.
Q9
The calorific value of a fuel is expressed in the unit called:
[A]. Kilo joule per litre
[B]. Kilogram per milliliter
[C]. Kilojoules per gram
[D]. Kilojoules per kilogram
Q10
Choose the incorrect statement from the following: “Forest fires are usually due to …”
[A]. Carelessness of humans
[B]. Heat of sun
[C]. Cutting of trees
[D]. Lightning Strike
Q11
Boojho is writing some statements about polyester. In which of the following statements is or are incorrect? Help him.
[A]. In the sun, heat and light are produced due to nuclear reactions.
[B]. The heat and light produced in the sun are ordinary combustion as like fire.
[C]. A substance which can burn are called combustible substances.
[D]. When a magnesium ribbon burns it combines with oxygen of air to form magnesium oxide and liberate heat and light.
Q12
Consider the following statements and choose the incorrect statement(s):
[A]. The burning of magnesium in air to produce heat and light is a combustion process.
[B]. When charcoal burns, then the carbon of charcoal combines with oxygen of air to form carbon dioxide.
[C]. A combustible substance is also called a fuel.
[D]. Those substances which can undergo combustion are called non-combustible substances.
Q13
Boojho is writing some sentences about condition for combustion. Choose the correct sentences and help him:
[A]. Heating the combustible substance to its ignition temperature.
[B]. Presence of a supporter of combustion like air or oxygen.
[C]. Presence of a combustible substance.
[D]. All the above.
Q14
The substance expected to have the highest ignition temperature out of the following is:
[A]. Kerosene
[B]. Petrol
[C]. Coal
[D]. Alcohol
Q15
Boojho is writing some statements about polyester. In which of the following statements is or are incorrect? Help him.
[A]. The lowest temperature at which substance catch fire and starts burning, is called its ignition temperature.
[B]. The substance which have very low ignition temperature and can easily catch fire with a flame are inflammable substances.
[C]. Coal has a high ignition temperature, so coal fire cannot be started by using a lighted matchstick directly.
[D]. None of the above
Q16
Mohan is writing some statements, choose the correct statements and help him:
[A]. When water is thrown on a burning substance it gets cooled below its ignition temperature and stops burning.
[B]. The fire produced by burning oil (frying pan) and petrol (petrol pumps, oil tanks etc.) cannot be extinguished by using water.
[C]. The fire caused by electrical short circuit in an electrical appliance or in electrical wiring should not be extinguished by throwing water.
[D]. All the above
Q17
Which of the following statement is or are incorrect?
[A]. A small fire can be extinguished by throwing sand or soil over it.
[B]. If the clothes of person working in the kitchen catch fire, the person is immediately covered with a blanket.
[C]. The combustion reaction in which a large amount of heat and light produced in a short time is called rapid combustion.
[D]. Any fire needs heat and combustible materials to occur.
Q18
On placing an inverted tumbler over a burning candle, the flame extinguishes after sometime. This is because of non-availability of:
[A]. Oxygen
[B]. Water vapors
[C]. Carbon dioxide
[D]. Wax
Q19
Boojho is writing some statements but he confused to know whether the statements are correct or not? Would you help him?
[A]. Rapid combustion is that type of combustion in which a large amount of heat and light are produced in a short time.
[B]. Spontaneous is that type of combustion in which reaction occurs on its own without helping of heat.
[C]. Explosive combustion is that type of combustion in which a large amount of heat, light and sound are produced in very fast way.
[D]. All the above.
Q20
Paheli is writing some statements but she confused to know whether the statements are incorrect or not? Would you help her?
[A]. Fuel is a material which is burnt to produce heat.
[B]. Different fuels produce different amount of heat on burning.
[C]. The amount of heat produced by the complete burning of 1 kg of a fuel is called its calorific value.
[D]. The calorific value of coal is much higher than the calorific value of LPG.
Q21
Saumya is writing about “ideal fuel” as ideal fuel is cheap easy to transfer and readily available in the market. Choose in correct sentences written by Saumya:
[A]. It does not produce harmful gases or do not leave any residue after burning.
[B]. It has a proper ignition temperature.
[C]. It can burn easily in air at a moderate rate.
[D]. It has a low calorific value for proper burning.
Q22
Which of the following is not a combustible substance?
[A]. Camphor
[B]. Glass
[C]. Straw
[D]. Alcohol
Q23
Which of the following has the highest calorific value?
[A]. Kerosene
[B]. Biogas
[C]. LPG
[D]. Petrol
Q24
A substance which reacts with oxygen giving heat is called a combustible substance. Which one of the following is a combustible substance?
[A]. Iron Nail
[B]. Glass
[C]. Stone
[D]. Wood
Q25
In which of the following sentences are incorrect?
[A]. A chemical process in which a substance reacts with oxygen to give off heat, is called combustion.
[B]. When the clothes of a person catch fire, the person is covered with the blanket to extinguish fire.
[C]. The lowest temperature at which a substance catches fire is called, its ignition temperature.
[D]. The substances which give very high ignition, temperature and can easily catch fire with a flame, are called inflammable substances.
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