Class 8 Combustion And Flame CBSE Questions & Answers

Class 8 · Combustion And Flame

This is Science Class 8 Combustion and Flame CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Gas necessary for combustion is:
  • A
    sulphur dioxide
  • B
    hydrogen
  • C
    oxygen
    Correct
  • D
    nitrogen
2
Combustion is a _____ chemical reaction:
  • A
    exothermic
    Correct
  • B
    non
  • C
    endothermic
  • D
    volatile
3
Substance that burns in oxygen to produce heat and light is called :
  • A
    combustible
    Correct
  • B
    limitless
  • C
    renewable
  • D
    non combustible
4
Substance that does not burn in air is :
  • A
    diesel
  • B
    sand
    Correct
  • C
    wood
  • D
    kerosene
5
Spontaneous combustion is a :
  • A
    slow process
    Correct
  • B
    used in internal combustion engines
  • C
    fast process
  • D
    both fast process & used in internal combustion engines
6
Cutting trees at large scale leads to :
  • A
    deforestation
    Correct
  • B
    reforestation
  • C
    afforestation
  • D
    both deforestation & afforestation
7
Amount of heat energy produced on complete combustion of 1kg of fuel is called :
  • A
    heat value
  • B
    combustion value
  • C
    energy value
  • D
    calorific value
    Correct
8
Substance which vaporises during burning forms :
  • A
    all the above
  • B
    carbon black
  • C
    residue
  • D
    flame
    Correct
9
Combustion is also called :
  • A
    conduction
  • B
    burning
    Correct
  • C
    induction
  • D
    all the above
10
Lowest temperature at which a substrate catches fire is called its :
  • A
    vaporising temperature
  • B
    ignition temperature
    Correct
  • C
    threshold temperature
  • D
    blackening temperature
11
A combustible substance is :-
  • A
    wax
    Correct
  • B
    glass
  • C
    water
  • D
    sand
12
Water works as a fire extinguisher by removing :-
  • A
    oxygen
  • B
    source of combustible substance
  • C
    heat
  • D
    both oxygen & heat
    Correct
13
We can extinguish fire by :-
  • A
    both cutting the supply of oxygen & lowering temperature below ignition temperature
    Correct
  • B
    removing non combustible substances from surroundings
  • C
    cutting the supply of oxygen
  • D
    lowering temperature below ignition temperature
14
Non combustible substances do not burn in :
  • A
    oxygen
  • B
    air
  • C
    both air & oxygen
    Correct
  • D
    hydrogen
15
The gas which supports combustion of coal is :
  • A
    hydrogen
  • B
    oxygen
    Correct
  • C
    nitrogen
  • D
    carbon dioxide