8th Class Science Combustion and Flame Question Bank

done Combustion and Flame Conceptive Objective Problems Total Questions - 9

• question_answer1)
  Four substances P, Q, R, and S were brought one by one near a lighted candle. It was observed that only substance Q bums readily. Substances P and R burn after sustained heating and substance S does not bum at all. Among all the substances given, which substance has the lowest ignition temperature?
  A)
   P                                            done clear
  B)
   Q done clear
  C)
   R                                            done clear
  D)
   S done clear
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• question_answer2)
  Which gas is used in fire extinguishers?
  A)
   \[{{O}_{2}}\]                                     done clear
  B)
   \[He\] done clear
  C)
   \[C{{O}_{2}}\]                   done clear
  D)
   \[CO\] done clear
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• question_answer3)
  Which of the following substances can be used to extinguish a fire in an oil well?
  A)
   Water                  done clear
  B)
   Sand done clear
  C)
   Carbon dioxide                done clear
  D)
   Sodium bicarbonate solution done clear
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• question_answer4)
                                                                                             Which of the following is not a characteristic of a good fuel?
  A)
   It should be cheap and readily available done clear
  B)
   It should have a high calorific value done clear
  C)
   It should be environment friendly done clear
  D)
   It should bum at a slow rate in air done clear
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• question_answer5)
   The calorific value of a fuel is 330000 kJ/kg. 0.9634 kg of the fuel is taken for combustion. The total amount of heat energy (in kJ) produced during combustion is
  A)
   317922            done clear
  B)
   215677 done clear
  C)
   3179.22                done clear
  D)
   317.922 done clear
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• question_answer6)
  4.120 kg of a fuel was burnt to produce 178000 kJ of energy. The calorific value (in kJ/kg) of the fuel is
  A)
   \[4.3203\times {{10}^{4}}\]         done clear
  B)
   \[4.3203\times {{10}^{3}}\] done clear
  C)
   \[4.3203\times {{10}^{2}}\]         done clear
  D)
   \[4.3203\times {{10}^{1}}\] done clear
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• question_answer7)
   Which of the following statements is correct?
  A)
   Liquefied Petroleum gas is a better domestic fuel than wood. done clear
  B)
   Fire produced by kerosene oil can be controlled using water. done clear
  C)
   A fuel can be heated to any temperature before it starts burning. done clear
  D)
   Water is used to control fires involving electrical equipment?s. done clear
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• question_answer8)
  Which of the following materials does not bum with. a flame?
  A)
   Kerosene          done clear
  B)
   Camphor done clear
  C)
   Wood                   done clear
  D)
   Wax done clear
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• question_answer9)
  Goldsmiths blow the outermost zone of flame with a blow-pipe for melting gold and silver. Why do they use the outermost zone?
  A)
   It is the zone of incomplete combustion and is least hot. done clear
  B)
   It is the zone of complete combustion and is the hottest zone. done clear
  C)
   It is the least hot zone and complete combustion takes place in this zone. done clear
  D)
   It is the hottest zone though incomplete combustion takes place in this zone. done clear
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