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
Anil was doing an experiment in his chemistry lab. He opened the air hole of Bunsen burner and adjusted it to get :
  • A
    green flame
  • B
    blue flame
    Correct
  • C
    yellow flame
  • D
    black flame
2
Which of following fuels will give us maximum energy ?
  • A
    glucose
  • B
    rice
  • C
    butter
    Correct
  • D
    pulses
3
Rahul brought a copper wire near the candle flame and found that it takes least time to become red hot when introduced into :
  • A
    middle zone of flame
  • B
    innermost zone of flame
  • C
    equal time in all zones of flame
  • D
    outermost zone of flame
    Correct
4
The type of combustion which can cause lot of air pollution is :
  • A
    spontaneous combustion
  • B
    incomplete combustion
    Correct
  • C
    slow combustion
  • D
    complete combustion
5
Combustion can be defined as a:-
  • A
    physical change
  • B
    cyclic change
  • C
    all of these
  • D
    chemical change
    Correct
6
Rekha was studying about combustible substances and she concluded that every combustible substance when burnt produce:
  • A
    methane
  • B
    Carbon monoxide
  • C
    heat
    Correct
  • D
    light
7
Another name given to ignition temperature is :
  • A
    kindling temperature
    Correct
  • B
    absolute temperature
  • C
    none of them
  • D
    critical temperature
8
Fuels are present in :
  • A
    gaseous state
  • B
    all of these
    Correct
  • C
    solid state
  • D
    liquid state
9
The contact number of a fire station or fire control room is :
  • A
    100
  • B
    545
  • C
    101
    Correct
  • D
    555
10
In villages, many people still use coal or wood to cook food. For easy combustion of such fuels :
  • A
    water is sprinkled
  • B
    soil is used to make layers
  • C
    air is blown around
    Correct
  • D
    sand is thrown on the stove
11
If a combustible substance is present along with fire :
  • A
    substance will not burn at all.
  • B
    substance will not catch fire above its ignition point.
  • C
    substance will not catch fire below its ignition point.
    Correct
  • D
    substance will catch fire immediately.
12
Gas that has very high calorific value is :
  • A
    oxygen
  • B
    chlorine
  • C
    nitrogen
  • D
    hydrogen
    Correct
13
A Soda acid fire extinguisher releases _____ which puts out the fire:
  • A
    water
    Correct
  • B
    carbon dioxide
  • C
    foam
  • D
    soda
14
When the fuel burns incompletely a poisonous gas is released that can be very harmful our life :
  • A
    chloro fluoro carbons
  • B
    carbon dioxide
  • C
    methane
  • D
    carbon monoxide
    Correct
15
In Swastik
  • A
    water float on oil
  • B
    oil float on water
    Correct
  • C
    oil float on carbon dioxide
  • D
    water float on oxygen