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8th Class Science Combustion and Flame Question Bank Combustion and Flame Formative Objective Problems

  • question_answer
    The   ignition   temperature   of   four substances I, II, III, and IV is \[{{25}^{o}}C\], \[{{35}^{o}}C\], \[{{40}^{o}}C\], and \[{{60}^{o}}C\] respectively. The substances that will catch fire at \[{{36}^{o}}C\] are _____i_____    and ______ii______. The remaining substances can be called _____iii_____  at this temperature. The information in which alternative completes the given statements?

    A)  
    i ii iii
    i II Non-flammable

    B)  
    i ii iii
    II III Non-flammable

    C)
    i ii iii
    III IV Non-flammable

    D)
    i ii iii
    IV I Non-flammable

    Correct Answer: A

    Solution :

      The ignition temperature of a substance is the minimum temperature at which it starts burning. A substance remains non-flammable below its ignition temperature. When substances I, II, III, and IV are heated to \[36{}^\circ C,\]only substances I and II will catch fire as their ignition temperatures are below the temperature provided to them. Substances III and IV with a higher ignition temperature will remain non-flammable at this temperature. The correct answer is A.


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