Test: Combustion And Flame - 4


20 Questions MCQ Test Class 8 Science by VP Classes | Test: Combustion And Flame - 4


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This mock test of Test: Combustion And Flame - 4 for Class 8 helps you for every Class 8 entrance exam. This contains 20 Multiple Choice Questions for Class 8 Test: Combustion And Flame - 4 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Combustion And Flame - 4 quiz give you a good mix of easy questions and tough questions. Class 8 students definitely take this Test: Combustion And Flame - 4 exercise for a better result in the exam. You can find other Test: Combustion And Flame - 4 extra questions, long questions & short questions for Class 8 on EduRev as well by searching above.
QUESTION: 1

The substances which give heat and light after combustion are called

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QUESTION: 2

Like fuels the sun also provides heat and light. The process taking place in the sun is called

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QUESTION: 3

Coal burns with

Solution: Charcoal is a solid fuel which does not vapouriseon heating. So, charcoal does not burn by producing a flame. It only glows on combustion.
QUESTION: 4

Burning of charcoal in a closed room will produce

Solution: Incomplete combustion of coal gives carbon monoxide gas. It is a very poisonous gas. It is dangerous to burn coal in a closed room. The carbon monoxide gas produced can kill persons sleeping in that room. So we should not sleep in a closed room with burning coal fire in it.
QUESTION: 5

The substances which have very low ignition temperature will

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QUESTION: 6

CNG and LPG are the examples of

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QUESTION: 7

Ignition temperature is

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QUESTION: 8

Combustion is a

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QUESTION: 9

The products of combustion are

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QUESTION: 10

There are following zones of a flame

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It is because there are only three zones in a flame i.e. dark zone, non luminous zone, luminous zone

QUESTION: 11

Coal is a fuel which can produce flame.

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QUESTION: 12

The innermost part of the flame has very least temperature.

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QUESTION: 13

CNG stands for Common Natural Gas.

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QUESTION: 14

Carbon monoxide is a poisonous gas.

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QUESTION: 15

Acid rain is very useful for the crops, buildings and the soil. 

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QUESTION: 16

Oxygen is required for the burning of any substance.

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QUESTION: 17

The lowest temperature at which any substance catches fire is called ignition temperature.

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QUESTION: 18

 Oxygen is the product of any burning process.

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QUESTION: 19

C.N.G. and L.P.G. burn with sooty flame

Solution:

They burn produced blue flame ,so they burn with a sooty flame.The blue is called "chemoluminescence". It's the light produced directly by the combustion reaction, and will therefore be present during most hydrocarbon fires. The yellow and orange (which provide most of the light from the actual fire) come from a more interesting source. When hydrocarbons burn without sufficient oxygen mixed in, they burn incompletely. This reaction produces tiny particles of solid carbon, which we generally refer to as 'soot'. The flame is full of this finely dispersed carbon, which gets heated by the combustion. A typical wood fire produces flames anywhere from 1000 K to 2000 K. At that temperature, the particles glow, giving off orange to yellow light. Those tiny bits of superhot carbon is what causes most of the light we see from fires.

Gas burners are generally designed to mix plenty of air in with the gas before it burns. so that incomplete combustion doesn't happen, soot doesn't get produced, and so all you see is the blue from the combustion. But if you block some of the air from getting into the burners, you'll find that gas flames burn just as yellow as wood.

QUESTION: 20

All the fuels burn with blue flame.

Solution:

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